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  • richardmitnick 1:03 pm on May 19, 2019 Permalink | Reply
    Tags: , , , Physics, Reversing traditional plasma shaping provides greater stability for fusion reactions.   

    From MIT News: “Steering fusion’s ‘D-turn'” 

    MIT News

    From MIT News

    May 17, 2019
    Paul Rivenberg | Plasma Science and Fusion Center

    1
    Cross sections of pressure profiles are shown in two different tokamak plasma configurations (the center of the tokamak doughnut is to the left of these). The discharges have high pressure in the core (yellow) that decreases to low pressure (blue) at the edge. Researchers achieved substantial high-pressure operation of reverse-D plasmas at the DIII-D National Fusion Facility.

    Image: Alessandro Marinoni/MIT PSFC

    Research scientist Alessandro Marinoni shows that reversing traditional plasma shaping provides greater stability for fusion reactions.

    Trying to duplicate the power of the sun for energy production on earth has challenged fusion researchers for decades. One path to endless carbon-free energy has focused on heating and confining plasma fuel in tokamaks, which use magnetic fields to keep the turbulent plasma circulating within a doughnut-shaped vacuum chamber and away from the walls. Fusion researchers have favored contouring these tokamak plasmas into a triangular or D shape, with the curvature of the D stretching away from the center of the doughnut, which allows plasma to withstand the intense pressures inside the device better than a circular shape.

    Led by research scientists Alessandro Marinoni of MIT’s Plasma Science and Fusion Center (PSFC) and Max Austin, of the University of Texas at Austin, researchers at the DIII-D National Fusion Facility have discovered promising evidence that reversing the conventional shape of the plasma in the tokamak chamber can create a more stable environment for fusion to occur, even under high pressure. The results were recently published in Physical Review Letters and Physics of Plasmas.

    3
    DIII-D National Fusion Facility. General Atomics

    Marinoni first experimented with the “reverse-D” shape, also known as “negative triangularity,” while pursuing his PhD on the TCV tokamak at Ecole Polytechnique Fédérale de Lausanne, Switzerland.

    4
    The Tokamak à configuration variable (TCV, literally “variable configuration tokamak”) is a Swiss research fusion reactor of the École polytechnique fédérale de Lausanne. Its distinguishing feature over other tokamaks is that its torus section is three times higher than wide. This allows studying several shapes of plasmas, which is particularly relevant since the shape of the plasma has links to the performance of the reactor. The TCV was set up in November 1992.

    The TCV team was able to show that negative triangularity helps to reduce plasma turbulence, thus increasing confinement, a key to sustaining fusion reactions.

    “Unfortunately, at that time, TCV was not equipped to operate at high plasma pressures with the ion temperature being close to that of electrons,” notes Marinoni, “so we couldn’t investigate regimes that are directly relevant to fusion plasma conditions.”

    Growing up outside Milan, Marinoni developed an interest in fusion through an early passion for astrophysical phenomena, hooked in preschool by the compelling mysteries of black holes.

    “It was fascinating because black holes can trap light. At that time I was just a little kid. As such, I couldn’t figure out why the light could be trapped by the gravitational force exerted by black holes, given that on Earth nothing like that ever happens.”

    As he matured he joined a local amateur astronomy club, but eventually decided black holes would be a hobby, not his vocation.

    “My job would be to try producing energy through nuclear fission or fusion; that’s the reason why I enrolled in the nuclear engineering program in the Polytechnic University of Milan.”

    After studies in Italy and Switzerland, Marinoni seized the opportunity to join the PSFC’s collaboration with the DIII-D tokamak in San Diego, under the direction of MIT professor of physics Miklos Porkolab. As a postdoc, he used MIT’s phase contrast imaging diagnostic to measure plasma density fluctuations in DIII-D, later continuing work there as a PSFC research scientist.

    Max Austin, after reading the negative triangularity results from TCV, decided to explore the possibility of running similar experiments on the DIII-D tokamak to confirm the stabilizing effect of negative triangularity. For the experimental proposal, Austin teamed up with Marinoni and together they designed and carried out the experiments.

    “The DIII-D research team was working against decades-old assumptions,” says Marinoni. “It was generally believed that plasmas at negative triangularity could not hold high enough plasma pressures to be relevant for energy production, because of macroscopic scale Magneto-Hydro-Dynamics (MHD) instabilities that would arise and destroy the plasma. MHD is a theory that governs the macro-stability of electrically conducting fluids such as plasmas. We wanted to show that under the right conditions the reverse-D shape could sustain MHD stable plasmas at high enough pressures to be suitable for a fusion power plant, in some respects even better than a D-shape.”

    While D-shaped plasmas are the standard configuration, they have their own challenges. They are affected by high levels of turbulence, which hinders them from achieving the high pressure levels necessary for economic fusion. Researchers have solved this problem by creating a narrow layer near the plasma boundary where turbulence is suppressed by large flow shear, thus allowing inner regions to attain higher pressure. In the process, however, a steep pressure gradient develops in the outer plasma layers, making the plasma susceptible to instabilities called edge localized modes that, if sufficiently powerful, would expel a substantial fraction of the built-up plasma energy, thus damaging the tokamak chamber walls.

    DIII-D was designed for the challenges of creating D-shaped plasmas. Marinoni praises the DIII-D control group for “working hard to figure out a way to run this unusual reverse-D shape plasma.”

    The effort paid off. DIII-D researchers were able to show that even at higher pressures, the reverse-D shape is as effective at reducing turbulence in the plasma core as it was in the low-pressure TCV environment. Despite previous assumptions, DIII-D demonstrated that plasmas at reversed triangularity can sustain pressure levels suitable for a tokamak-based fusion power plant; additionally, they can do so without the need to create a steep pressure gradient near the edge that would lead to machine-damaging edge localized modes.

    Marinoni and colleagues are planning future experiments to further demonstrate the potential of this approach in an even more fusion-power relevant magnetic topology, based on a “diverted” tokamak concept. He has tried to interest other international tokamaks in experimenting with the reverse configuration.

    “Because of hardware issues, only a few tokamaks can create negative triangularity plasmas; tokamaks like DIII-D, that are not designed to produce plasmas at negative triangularity, need a significant effort to produce this plasma shape. Nonetheless, it is important to engage the fusion community worldwide to more fully establish the data base on the benefits of this shape.”

    Marinoni looks forward to where the research will take the DIII-D team. He looks back to his introduction to tokamak, which has become the focus of his research.

    “When I first learned about tokamaks I thought, ‘Oh, cool! It’s important to develop a new source of energy that is carbon free!’ That is how I ended up in fusion.”

    This research is sponsored by the U.S. Department of Energy Office of Science’s Fusion Energy Sciences, using their DIII-D National Fusion Facility.

    See the full article here .


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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 11:42 am on May 17, 2019 Permalink | Reply
    Tags: Articles about them inevitably refer to entanglement- a property of quantum physics that makes all these magical devices possible., , Physics, Quantum computers; quantum cryptography; and quantum (insert name here) are often in the news these days., ,   

    From University of Toronto: “Remote connections? U of T expert on detangling entanglement in quantum physics” 

    U Toronto Bloc

    From University of Toronto

    April 26, 2019
    Amar Vutha

    1
    Entanglement is a “quantum correlation” between the properties of particles (image by Shutterstock)

    Quantum computers, quantum cryptography and quantum (insert name here) are often in the news these days. Articles about them inevitably refer to entanglement, a property of quantum physics that makes all these magical devices possible.

    Einstein called entanglement “spooky action at a distance,” a name that has stuck and become increasingly popular. Beyond just building better quantum computers, understanding and harnessing entanglement is also useful in other ways.

    For example, it can be used to make more accurate measurements of gravitational waves, and to better understand the properties of exotic materials. It also subtly shows up in other places: I have been studying how atoms bumping into each other become entangled, to understand how this affects the accuracy of atomic clocks.

    But what is entanglement? Is there some way to understand this “spooky” phenomenon? I will try to explain it by bringing together two notions from physics: conservation laws and quantum superpositions.

    Conservation laws

    Conservation laws are some of the deepest and most pervasive concepts in all of physics. The law of conservation of energy states that the total amount of energy in an isolated system remains fixed (although it can be converted from electrical energy to mechanical energy to heat, and so on). This law underlies the workings of all of our machines, whether they are steam engines or electric cars. Conservation laws are a kind of accounting statement: You can exchange bits of energy around, but the total amount has to stay the same.

    Conservation of momentum (momentum being mass times velocity) is the reason why, when two ice skaters with different masses push off from each other, the lighter one moves away faster than the heavier. This law also underlies the famous dictum that “every action has an equal and opposite reaction.” Conservation of angular momentum is why – going back to ice skaters again – a whirling figure skater can spin faster by drawing her arms closer to her body.

    2
    France’s Gabriella Papadakis and Guillaume Cizeron demonstrate the effects of conservation laws during the 2019 ISU European Figure Skating Championships in Belarus (photo by Shutterstock)

    These conservation laws have been experimentally verified to work across an extraordinary range of scales in the universe, from black holes in distant galaxies all the way down to the tiniest spinning electrons.

    Quantum addition

    Picture yourself on a nice hike through the woods. You come to a fork in the trail, but you find yourself struggling to decide whether to go left or right. The path to the left looks dark and gloomy but is reputed to lead to some nice views, while the one to the right looks sunny but steep. You finally decide to go right, wistfully wondering about the road not taken. In a quantum world, you could have chosen both.

    For systems described by quantum mechanics (that is, things that are sufficiently well isolated from heat and external disturbances), the rules are more interesting. Like a spinning top, an electron for example can be in a state where it spins clockwise, or in another state where it spins anticlockwise. Unlike a spinning top though, it can also be in a state that is [clockwise spinning] + [anticlockwise spinning].

    The states of quantum systems can be added together and subtracted from each other. Mathematically, the rules for combining quantum states can be described in the same way as the rules for adding and subtracting vectors. The word for such a combination of quantum states is a superposition. This is really what is behind strange quantum effects that you may have heard about, such as the double-slit experiment, or particle-wave duality.


    PBS Studios: The Double-Slit Experiment. 13 minutes

    Say you decide to force an electron in the [clockwise spinning] + [anticlockwise spinning] superposition state to yield a definite answer. Then the electron randomly ends up either in the [clockwise spinning] state or in the [anticlockwise spinning] state. The odds of one outcome versus the other are easy to calculate (with a good physics book at hand). The intrinsic randomness of this process may bother you if your worldview requires the universe to behave in a completely predictable way, but … c’est la (experimentally tested) vie.

    Conservation laws and quantum mechanics

    Let’s put these two ideas together now, and apply the law of conservation of energy to a pair of quantum particles.

    Imagine a pair of quantum particles (say atoms) that start off with a total of 100 units of energy. You and your friend separate the pair, taking one each. You find that yours has 40 units of energy. Using the law of conservation of energy, you deduce that the one your friend has must have 60 units of energy. As soon as you know the energy of your atom, you immediately also know the energy of your friend’s atom. You would know this even if your friend never revealed any information to you. And you would know this even if your friend was off on the other side of the galaxy at the time you measured the energy of your atom. Nothing spooky about it (once you realize this is just correlation, not causation).

    But the quantum states of a pair of atoms can be more interesting. The energy of the pair can be partitioned in many possible ways (consistent with energy conservation, of course). The combined state of the pair of atoms can be in a superposition, for example: [your atom: 60 units; friend’s atom: 40 units] + [your atom: 70 units; friend’s atom: 30 units].

    This is an entangled state of the two atoms. Neither your atom, nor your friend’s, has a definite energy in this superposition. Nevertheless, the properties of the two atoms are correlated because of conservation of energy: Their energies always add up to 100 units.

    For example, if you measure your atom and find it in a state with 70 units of energy, you can be certain that your friend’s atom has 30 units of energy. You would know this even if your friend never revealed any information to you. And thanks to energy conservation, you would know this even if your friend was off on the other side of the galaxy.

    Nothing spooky about it.The Conversation

    See the full article here .


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    Please help promote STEM in your local schools.

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    Founded in 1827, the University of Toronto has evolved into Canada’s leading institution of learning, discovery and knowledge creation. We are proud to be one of the world’s top research-intensive universities, driven to invent and innovate.

    Our students have the opportunity to learn from and work with preeminent thought leaders through our multidisciplinary network of teaching and research faculty, alumni and partners.

    The ideas, innovations and actions of more than 560,000 graduates continue to have a positive impact on the world.

     
  • richardmitnick 8:41 am on May 16, 2019 Permalink | Reply
    Tags: A slippery surface for liquids with very low surface tension promotes droplet formation facilitating heat transfer., , , Physics, Specialized thin coatings   

    From MIT News: “New surface treatment could improve refrigeration efficiency” 

    MIT News
    MIT Widget

    From MIT News

    May 15, 2019
    David L. Chandler

    1
    Specialized thin coatings developed by the MIT team cause even low-surface-tension fluids to readily form droplets on the surface of a pipe, as seen here, which improves the efficiency of heat transfer. Image courtesy of the researchers

    2
    Artistic rendition of a dropwise condensing shell and tube heat exchanger, where vapor molecules condense onto heat exchange tubes and form drops that shed from the surface. The different colors and shapes represent different vapor materials. Illustration by Demin Liu

    A slippery surface for liquids with very low surface tension promotes droplet formation, facilitating heat transfer.

    Unlike water, liquid refrigerants and other fluids that have a low surface tension tend to spread quickly into a sheet when they come into contact with a surface. But for many industrial processes it would be better if the fluids formed droplets, which could roll or fall off the surface and carry heat away with them.

    Now, researchers at MIT have made significant progress in promoting droplet formation and shedding in such fluids. This approach could lead to efficiency improvements in many large-scale industrial processes including refrigeration, thus saving energy and reducing greenhouse gas emissions.

    The new findings are described in the journal Joule, in a paper by graduate student Karim Khalil, professor of mechanical engineering Kripa Varanasi, professor of chemical engineering and Associate Provost Karen Gleason, and four others.

    Over the years, Varanasi and his collaborators have made great progress in improving the efficiency of condensation systems that use water, such as the cooling systems used for fossil-fuel or nuclear power generation. But other kinds of fluids — such as those used in refrigeration systems, liquification, waste heat recovery, and distillation plants, or materials such as methane in oil and gas liquifaction plants — often have very low surface tension compared to water, meaning that it is very hard to get them to form droplets on a surface. Instead, they tend to spread out in a sheet, a property known as wetting.

    But when these sheets of liquid coat a surface, they provide an insulating layer that inhibits heat transfer, and easy heat transfer is crucial to making these processes work efficiently. “If it forms a film, it becomes a barrier to heat transfer,” Varanasi says. But that heat transfer is enhanced when the liquid quickly forms droplets, which then coalesce and grow and fall away under the force of gravity. Getting low-surface-tension liquids to form droplets and shed them easily has been a serious challenge.

    In condensing systems that use water, the overall efficiency of the process can be around 40 percent, but with low-surface-tension fluids, the efficiency can be limited to about 20 percent. Because these processes are so widespread in industry, even a tiny improvement in that efficiency could lead to dramatic savings in fuel, and therefore in greenhouse gas emissions, Varanasi says.

    By promoting droplet formation, he says, it’s possible to achieve a four- to eightfold improvement in heat transfer. Because the condensation is just one part of a complex cycle, that translates into an overall efficiency improvement of about 2 percent. That may not sound like much, but in these huge industrial processes even a fraction of a percent improvement is considered a major achievement with great potential impact. “In this field, you’re fighting for tenths of a percent,” Khalil says.

    Unlike the surface treatments Varanasi and his team have developed for other kinds of fluids, which rely on a liquid material held in place by a surface texture, in this case they were able to accomplish the fluid-repelling effect using a very thin solid coating — less than a micron thick (one millionth of a meter). That thinness is important, to ensure that the coating itself doesn’t contribute to blocking heat transfer, Khalil explains.

    The coating, made of a specially formulated polymer, is deposited on the surface using a process called initiated chemical vapor deposition (iCVD), in which the coating material is vaporized and grafts onto the surface to be treated, such as a metal pipe, to form a thin coating. This process was developed at MIT by Gleason and is now widely used.

    The authors optimized the iCVD process by tuning the grafting of coating molecules onto the surface, in order to minimize the pinning of condensing droplets and facilitate their easy shedding. The process could be carried out on location in industrial-scale equipment, and could be retrofitted into existing installations to provide a boost in efficiency. The process is “materials agnostic,” Khalil says, and can be applied on either flat surfaces or tubing made of stainless steel, titanium, or other metals commonly used in condensation heat-transfer processes that involve these low-surface-tension fluids. “Whatever materials are used in your facility’s heat exchanger, it tends to be scalable with this process,” he adds.

    The net result is that on these surfaces, condensing fluids like the hydrocarbons pentane or liquid methane, or alcohols like ethanol, will readily form small droplets that quickly fall off the surface, making room for more to form, and in the process shedding heat from the metal to the droplets that fall away.

    One area where such coatings could play a useful role, Varanasi says, is in organic Rankine cycle systems, which are widely used for generating power from waste heat in a variety of industrial processes. “These are inherently inefficient systems,” he says, “but this could make them more efficient.”

    3
    The new coating is shown promoting condensation on a titanium surface, a material widely used in industrial heat exchangers.

    “This new approach to condensation is significant because it promotes drop formation (rather than film formation) even for low-surface-tension fluids, which significantly improves the heat transfer efficiency,” says Jonathan Boreyko, an assistant professor of mechanical engineering at Virginia Tech, who was not connected to this research. While the iCVD process itself is not new, he says, “showing here that it can be used even for the condensation of low-surface-tension fluids is of significant practical importance, as many real-life phase-change systems do not use water.”

    Saying the work is “of very high quality,” Boreyko adds that “simply showing for the first time that a thin, durable, and dry coating can promote the dropwise condensation of low-surface-tension fluids is very important for a wide variety of practical condenser systems.”

    The research was supported by the Shell-MIT Energy Initiative partnership. The team included former MIT graduate students Taylor Farnham and Adam Paxson, and former postdocs Dan Soto and Asli Ugur Katmis.

    See the full article here .


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    Please help promote STEM in your local schools.


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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 2:20 pm on May 14, 2019 Permalink | Reply
    Tags: , , , , LS2, , , Physics, Superconducting magnet circuits   

    From CERN: “LS2 Report: consolidating the energy extraction systems of LHC superconducting magnet circuits” 

    Cern New Bloc

    Cern New Particle Event


    From CERN

    13 May, 2019
    Anaïs Schaeffer

    1
    The LS2 team from the NRC Kurchatov-IHEP Institute, Protvino, Russia, with a 13 kA energy extraction system (Image: NRC Kurchatov-IHEP Institute)

    In the LHC, 1232 superconducting dipole magnets and 392 quadrupole magnets guide and focus the beams around the accelerator’s 27-kilometre ring, which is divided into eight sectors. These magnets operate at very low temperatures – 1.9 K or −271.3 °C – where even a tiny amount of energy released inside a magnet can warm its windings to above the critical temperature, causing the loss of superconductivity: this is called a quench. When this happens, the energy stored in the affected magnet has to be safely extracted in a short time to avoid damage to the magnet coil.

    To do so, two protection elements are activated: at the level of the quenching magnet, a diode diverts the current into a parallel by-pass circuit in less than a second; at the level of the circuit, 13 kA energy extraction systems absorb the energy of the whole magnet circuit in a few minutes. There are equivalent extraction systems installed for about 200 corrector circuits with currents up to 600 A.

    “In the framework of a long-lasting and fruitful collaboration between CERN and the Russian Federation, energy extraction systems for quench protection of the LHC superconducting magnets were designed in close partnership with two Russian institutes, the NRC Kurchatov-IHEP Institute in Protvino for the 13 kA systems and the Budker Institute in Novosibirsk for the 600 A systems. Russian industry was involved in the manufacturing of the parts of these systems,” explains Félix Rodríguez Mateos, leader of the Electrical Engineering (EE) section in the Machine Protection and Electrical Integrity (MPE) group of CERN’s Technology department.

    With a wealth of expertise and know-how, the Russian teams have continuously provided invaluable support to the MPE group. “Our Russian colleagues come to CERN for every year-end technical stop (YETS) and long shutdown to help us perform preventive maintenance and upgrade activities on the energy extraction systems,” says Rodríguez Mateos.

    During LS2, an extensive maintenance campaign is being performed on the 13 kA systems, which already count 10 years of successful operation in the LHC. “We are currently replacing an element, the arcing contact, in each one of the 256 electromechanical switches of the energy extraction systems to ensure their continuous reliable operation throughout the next runs,” adds Rodríguez Mateos. “In February, we fully replaced 32 switches at Point 8 of the accelerator in anticipation of consolidation for the future HL-LHC.”

    During LS2, the Electrical Engineering section is involved in many other activities that will be the subject of future articles.

    See the full article here.


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    Meet CERN in a variety of places:

    Quantum Diaries
    QuantumDiaries

    Cern Courier

     
  • richardmitnick 12:04 pm on May 14, 2019 Permalink | Reply
    Tags: >Model-dependent vs model-independent research, , , , , , , , , , Physics,   

    From Symmetry: “Casting a wide net” 

    Symmetry Mag
    From Symmetry

    05/14/19
    Jim Daley

    1
    Illustration by Sandbox Studio, Chicago

    In their quest to discover physics beyond the Standard Model, physicists weigh the pros and cons of different search strategies.

    On October 30, 1975, theorists John Ellis, Mary K. Gaillard and D.V. Nanopoulos published a paper [Science Direct] titled “A Phenomenological Profile of the Higgs Boson.” They ended their paper with a note to their fellow scientists.

    “We should perhaps finish with an apology and a caution,” it said. “We apologize to experimentalists for having no idea what is the mass of the Higgs boson… and for not being sure of its couplings to other particles, except that they are probably all very small.

    “For these reasons, we do not want to encourage big experimental searches for the Higgs boson, but we do feel that people performing experiments vulnerable to the Higgs boson should know how it may turn up.”

    What the theorists were cautioning against was a model-dependent search, a search for a particle predicted by a certain model—in this case, the Standard Model of particle physics.

    Standard Model of Particle Physics

    It shouldn’t have been too much of a worry. Around then, most particle physicists’ experiments were general searches, not based on predictions from a particular model, says Jonathan Feng, a theoretical particle physicist at the University of California, Irvine.

    Using early particle colliders, physicists smashed electrons and protons together at high energies and looked to see what came out. Samuel Ting and Burton Richter, who shared the 1976 Nobel Prize in physics for the discovery of the charm quark, for example, were not looking for the particle with any theoretical prejudice, Feng says.

    That began to change in the 1980s and ’90s. That’s when physicists began exploring elegant new theories such as supersymmetry, which could tie up many of the Standard Model’s theoretical loose ends—and which predict the existence of a whole slew of new particles for scientists to try to find.

    Of course, there was also the Higgs boson. Even though scientists didn’t have a good prediction of its mass, they had good motivations for thinking it was out there waiting to be discovered.

    And it was. Almost 40 years after the theorists’ tongue-in-cheek warning about searching for the Higgs, Ellis found himself sitting in the main auditorium at CERN next to experimentalist Fabiola Gianotti, the spokesperson of the ATLAS experiment at the Large Hadron Collider who, along with CMS spokesperson Joseph Incandela, had just co-announced the discovery of the particle he had once so pessimistically described.

    CERN CMS Higgs Event


    CERN ATLAS Higgs Event

    Model-dependent vs model-independent

    Scientists’ searches for particles predicted by certain models continue, but in recent years, searches for new physics independent of those models have begun to enjoy a resurgence as well.

    “A model-independent search is supposed to distill the essence from a whole bunch of specific models and look for something that’s independent of the details,” Feng says. The goal is to find an interesting common feature of those models, he explains. “And then I’m going to just look for that phenomenon, irrespective of the details.”

    Particle physicist Sara Alderweireldt uses model-independent searches in her work on the ATLAS experiment at the Large Hadron Collider.

    CERN ATLAS Image Claudia Marcelloni CERN/ATLAS

    Alderweireldt says that while many high-energy particle physics experiments are designed to make very precise measurements of a specific aspect of the Standard Model, a model-independent search allows physicists to take a wider view and search more generally for new particles or interactions. “Instead of zooming in, we try to look in as many places as possible in a consistent way.”

    Such a search makes room for the unexpected, she says. “You’re not dependent on the prior interpretation of something you would be looking for.”

    Theorist Patrick Fox and experimentalist Anadi Canepa, both at Fermilab, collaborate on searches for new physics.


    In Canepa’s work on the CMS experiment, the other general-purpose particle detector at the LHC, many of the searches are model-independent.

    While the nature of these searches allows them to “cast a wider net,” Fox says, “they are in some sense shallower, because they don’t manage to strongly constrain any one particular model.”

    At the same time, “by combining the results from many independent searches, we are getting closer to one dedicated search,” Canepa says. “Developing both model-dependent and model-independent searches is the approach adopted by the CMS and ATLAS experiments to fully exploit the unprecedented potential of the LHC.”

    Driven by data and powered by machine learning

    Model-dependent searches focus on a single assumption or look for evidence of a specific final state following an experimental particle collision. Model-independent searches are far broader—and how broad is largely driven by the speed at which data can be processed.

    “We have better particle detectors, and more advanced algorithms and statistical tools that are enabling us to understand searches in broader terms,” Canepa says.

    One reason model-independent searches are gaining prominence is because now there is enough data to support them. Particle detectors are recording vast quantities of information, and modern computers can run simulations faster than ever before, she says. “We are able to do model-independent searches because we are able to better understand much larger amounts of data and extreme regions of parameter and phase space.”

    Machine-learning is a key part of this processing power, Canepa says. “That’s really a change of paradigm, because it really made us make a major leap forward in terms of sensitivity [to new signals]. It really allows us to benefit from understanding the correlations that we didn’t capture in a more classical approach.”

    These broader searches are an important part of modern particle physics research, Fox says.

    “At a very basic level, our job is to bequeath to our descendants a better understanding of nature than we got from our ancestors,” he says. “One way to do that is to produce lots of information that will stand the test of time, and one way of doing that is with model-independent searches.”

    Models go in and out of fashion, he adds. “But model-independent searches don’t feel like they will.”

    See the full article here .


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 10:45 am on May 14, 2019 Permalink | Reply
    Tags: , “Tractor beam”, “What I want to do is understand these complex biological processes using the laws and tools of physics.”, , For Lee these multidisciplinary projects reflect the essence of his chosen calling: biophysics., , Lee is also able to generate ultra-high resolution images of neuron development for research aimed at finding improved treatments for degenerative diseases., Lee is principal investigator on a $1.5 million Department of Energy project—with his Rutgers team (Shishir Chundawat; Eric Lam; and Laura Fabris), Lee says “I became determined to understand biological processes through the simple universal and beautiful principles of physics.”, Lee’s device allows him to examine live plant cells in “unprecedented molecular detail” for a project that could help break new ground in the development of biofuels., Physics, Rutgers physicist Sang-Hyuk Lee, , The development of optical tweezers goes back decades., The instrument uses a focused laser beam to trap hold and move microscopic objects that previously had been too tiny to touch.   

    From Rutgers University: “Once a Dream of Science Fiction, a Laser Tweezer Helps a Rutgers Biophysicist Boldly Go Where Molecules Move” 

    Rutgers smaller
    Our Great Seal.

    From Rutgers University

    THIS POST IS DEDICATED TO L.Z. OF RUTGERS UNIVERSITY PHYSICS AND H.P.

    5.14.19
    John Chadwick

    Sang-Hyuk Lee integrates two Nobel Prize-winning innovations.

    1
    Sang-Hyuk Lee

    “An old dream of science fiction,” the Nobel Prize Committee said in its praise of the invention.

    Like the “tractor beam” of vintage Star Trek episodes others observed.

    The futuristic device they’re talking about is optical tweezers.

    Invented by Arthur Ashkin, one of three pioneers in laser physics to win the 2018 Nobel Prize in Physics, the instrument uses a focused laser beam to trap, hold, and move microscopic objects that previously had been too tiny to touch.

    2
    Sang-Hyuk Lee with Nobel Prize winning device, “tractor beam”

    The revolutionary tool is essential to the work of a Rutgers professor who recently brought the technology to the university. Sang-Hyuk Lee, of the Department of Physics and Astronomy, School of Arts and Sciences, has also added advanced microscopy techniques to make the device capable of examining and visualizing molecules at the tiniest level.

    He is using the innovative instrument for several federally-funded research projects that combine elements of physics and biology.

    Lee’s device allows him to examine live plant cells in “unprecedented molecular detail” for a project that could help break new ground in the development of biofuels. He is also able to generate ultra-high resolution images of neuron development for research aimed at finding improved treatments for degenerative diseases.

    For Lee, these multidisciplinary projects reflect the essence of his chosen calling: biophysics.

    “A biophysicist is bridging the gap between two worlds,” he says. “What I want to do is understand these complex biological processes using the laws and tools of physics.”

    The optical tweezers provide him with the perfect tool for that mission.

    The development of optical tweezers goes back decades. Ashkin, who was the head of laser science at Bell Labs in Holmdel, N.J., from 1963 to 1987, set out to build an instrument capable of grabbing particles, atoms, molecules, and living cells with “laser beam fingers,” according to NobelPrize.org. A major breakthrough came in 1987, when Ashkin succeeded in capturing living bacteria without harming them.

    Optical tweezers can move and manipulate particles smaller than a micron. A single strand of human hair is about 75 microns in width.

    Lee became intrigued by the technology while working on his doctorate at New York University under David Grier, a physicist who created more complex versions of optical tweezers by adding digital holography. Lee was also influenced by, and later worked as a post-doc for Carlos Bustamante, a biophysicist at the University of California, Berkeley, who used optical tweezers to stretch a single DNA molecule to measure the force holding it together.

    “His work completely changed my views of biology,” Lee says. “I became determined to understand biological processes through the simple, universal, and beautiful principles of physics.”

    After arriving at Rutgers in 2015, Lee designed and built the mammoth instrument that’s now housed within a glass enclosure in a laboratory at the Institute for Quantitative Biomedicine on Busch Campus. The device is far more versatile than commercially available models because Lee integrated a number of advanced optics techniques, including use of multiple lasers, and a technology known as super resolution fluorescence microscopy, which won the 2014 Nobel in Chemistry for producing higher resolution image than what conventional light microscopes could achieve.

    “So, we can get super-resolution image of intra-cellular structures while we exert measure force on individual molecules,” he says. “Our instrument is a one-of-a-kind, home-built microscope.”

    Physics Chair Robert Bartynski agrees. And he said the application of laser physics to contemporary problems in biology is opening an exciting new chapter in interdisciplinary science.

    4
    Nobel Prize winning device, “Tractor Beam”

    “The optical tweezers technology that Sang-Hyuk has developed at Rutgers give us a singular capability that expands our understanding of how biomolecules move in and around cells to carry out critical tasks,” Bartynski said. “The ability to manipulate and visualize individual molecules with these advanced optical techniques, will give unprecedented insights into the physics behind key biological processes

    Lee is principal investigator on a $1.5 million Department of Energy project—with his Rutgers team (Shishir Chundawat, Eric Lam and Laura Fabris), along with collaborators at Vanderbilt University and Oak Ridge National Laboratory—that seeks to understand how cell walls in plants are formed—knowledge that may accelerate the development of genetically engineered crops for use as renewable fuels and have broad impact on molecular and cellular biology fields in general.

    He is also involved in a National Science Foundation-funded project—with Nada N. Boustany, a Rutgers professor of biomedical engineering serving as principal investigator—that could help improve treatments for degenerative neural diseases or nerve injury due to trauma.

    Lee describes his research focus as “single-molecule biophysics,” the study of individual biomolecules to understand how they carry out their functions in living cells.

    “The application to important biology problems is still in its infancy,” he says. “This emerging field has tremendous potential.

    See the full article here .


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    Rutgers, The State University of New Jersey, is a leading national research university and the state’s preeminent, comprehensive public institution of higher education. Rutgers is dedicated to teaching that meets the highest standards of excellence; to conducting research that breaks new ground; and to providing services, solutions, and clinical care that help individuals and the local, national, and global communities where they live.

    Founded in 1766, Rutgers teaches across the full educational spectrum: preschool to precollege; undergraduate to graduate; postdoctoral fellowships to residencies; and continuing education for professional and personal advancement.

    As a ’67 graduate of University college, second in my class, I am proud to be a member of

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  • richardmitnick 11:55 am on May 13, 2019 Permalink | Reply
    Tags: , , Buildings of the future may be lit by collections of glowing plants and designed around an infrastructure of sunlight harvesting water transport and soil collecting and composting systems., , Collaboration between MIT architect and chemical engineer could be at the center of new sustainable infrastructure for buildings., , Nanobionic plant technology, Physics   

    From MIT News: “Ambient plant illumination could light the way for greener buildings” 

    MIT News
    MIT Widget

    From MIT News

    May 9, 2019
    Becky Ham

    Collaboration between MIT architect and chemical engineer could be at the center of new sustainable infrastructure for buildings.

    1
    Glowing nanobionic watercress plants illuminate the Plant Properties Reading Room. Image: KVA Matx and Strano Research Group

    2
    Glowing nanobionic watercress illuminates the book “Paradise Lost.” Image: Strano Research Group

    3
    Pollinator Port – A Plant Properties room featuring an access port for light and pollinators to reach interior plants. Image: KVA Matx and Strano Research Group

    Buildings of the future may be lit by collections of glowing plants and designed around an infrastructure of sunlight harvesting, water transport, and soil collecting and composting systems. That’s the vision behind an interdisciplinary collaboration between an MIT architecture professor and a professor of chemical engineering.

    The light-emitting plants, which debuted in 2017, are not genetically modified to produce light. Instead, they are infused with nanoparticles that turn the plant’s stored energy into light, similar to how fireflies glow. “The transformation makes virtually any plant a sustainable, potentially revolutionary technology,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT. “It promises lighting independent of an electrical grid, with ‘batteries’ you never need to charge, and power lines that you never need to lay.”

    But Strano and his colleagues soon realized that they needed partners who could expand the concept and understand its challenges and potential as part of a future of sustainable energy. He reached out to Sheila Kennedy, professor of architecture at MIT and principal at Kennedy and Violich Architecture, who is known for her work in clean energy infrastructure.

    “The science was so new and emergent that it seemed like an interesting design challenge,” says Kennedy. “The work of this design needed to move to a different register, which went beyond the problem of how the plant nanobionics could be demonstrated in architecture. As a design team, we considered some fundamental questions, such as how to understand and express the idea of plant lighting as a living, biological technology and how to invite the public to imagine this new future with plants.”

    “If we treat the development of the plant as we would just another light bulb, that’s the wrong way to go,” Strano adds.

    In 2017, Kennedy and Strano received a Professor Amar G. Bose Research Grant to build on their collaboration. The MIT faculty grants support unconventional, ahead-of-the-curve, and often interdisciplinary research endeavors that are unlikely to be funded through traditional avenues, yet have the potential to lead to big breakthroughs.

    Their first year of the Bose grant yielded several generations of the light-emitting watercress plants, which shine longer and brighter than the first experimental versions. The team is evaluating a new component to the nanobiotic plants that they call light capacitor particles. The capacitor, in the form of infused nanoparticles in the plant, stores spikes in light generation and “bleeds them out over time,” Strano explains. “Normally the light created in the biochemical reaction can be bright but fades quickly over time. Capacitive particles extend the duration of the generated plant light from hours to potentially days and weeks.”

    The researchers have added to their original patent on the light-emitting plant concept, filing a new patent on the capacitor and other components as well, Strano says.

    Designing for display

    As the nanobionic plant technology has advanced, the team is also envisioning how people might interact with the plants as part of everyday life. The architectural possibilities of their light-emitting plant will be on display within a new installation, “Plant Properties, a Future Urban Development,” at the Cooper Hewitt, Smithsonian Design Museum in New York opening May 10.

    Visitors to the installation, part of the 2019 “Nature—Cooper Hewitt Design Triennial” exhibition, can peek into a scaled architectural model of a New York City tenement building — which also serves as a plant incubator — to see the plants at work. The installation also demonstrates a roadmap for how an existing residential building could be adapted and transformed by design to support the natural growth of plants in a future when available energy could be very limited.

    “In Plant Properties, the nanobionic plant-based infrastructure is designed to use nature’s own resources,” says Kennedy. “The building harvests and transports sunlight, collects and recycles water, and enriches soil with compost.”

    The invitation to contribute to the Cooper Hewitt exhibition offered an unexpected way to demonstrate the plants’ possibilities, but designing an exhibit brought about a whole new set of challenges, Kennedy explains. “In the world of design museums, you’re usually asked to show something that’s already been exhibited, but this is new work and a new milestone in this project.”

    “We learned a lot about the care of plants,” Strano adds. “It’s one thing to make a laboratory demonstration, but it’s another entirely to make 33 continuous weeks of a public demonstration.”

    The researchers had to come up with a way to showcase the plants in a low-light museum environment where dirt and insects attracted by living plants are usually banished. “But rather than seeing this as a sort of insurmountable obstacle,” says Kennedy, “we realized that this kind of situation — how do you enable living plants to thrive in the enclosed setting of a museum — exactly paralleled the architectural problem of how to support significant quantities of plants growing inside buildings.”

    In the installation, multiple peepholes into the building model offer glimpses into the ways people in the building are living with the plants. Museum visitors are encouraged to join the experiment and crowdsource information on plant growth and brightness, by uploading their own photos of the plants to Instagram and tagging the MIT Plant Nanobiotics lab, using @plantproperties.

    The team is also collecting data on how the plants respond to the nanoparticles and other potential stresses. “The plants are actually under more stress from being in the museum environment than from the modifications that we introduce, but these effects need to be studied and mitigated if we are to use plants for indoor lighting,” Strano notes.

    Bright and nurturing futures

    Kennedy and Strano say the plants could be at the center of a new — but also “pre-eclectic” — idea in architecture.

    For most of human history, Kennedy explains, natural processes from sunlight to waste composting were part of the essential infrastructure of buildings. But these processes have been excluded in modern thinking or hidden away, preventing people from coming face to face with the environmental costs of energy infrastructure made from toxic materials and powered by fossil fuels.

    “People don’t question the impacts of our own mainstream electrical grid today. It’s very vulnerable, it’s very brittle, it’s so very wasteful and it’s also full of toxic material,” she says. “We don’t question this, but we need to.”

    “Lighting right now consumes a vast portion of our energy demand, approaching close to 20 percent of our global energy consumption, generating two gigatons of carbon dioxide per year,” Strano adds. “Consider that the plants replace more than just the lamp on your desk. There’s an enormous energy footprint that could potentially be replaced by the light-emitting plant.”

    The team is continuing to work on new ways to infuse the nanoparticles in the plants, so that they work over the lifetime of the plant, as well as experimenting on larger plants such as trees. But for the plants to thrive, architects will have to develop building infrastructure that integrates the plants into a new internal ecosystem of sunlight, water and waste disposal, Kennedy says.

    “If plants are to provide people with light, we need to keep plants healthy to benefit from everything they provide for us,” she says. “We think this is going to trigger a much more caring or nurturing relationship of people and their plants, or plants and the people that they illuminate.”

    See the full article here .


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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 11:10 am on May 13, 2019 Permalink | Reply
    Tags: "Better Microring Sensors for Optical Applications", , , Microring sensors, , , Physics   

    From Michigan Technical University: “Better Microring Sensors for Optical Applications” 

    Michigan Tech bloc

    From Michigan Technical University

    May 10, 2019
    Kelley Christensen

    1
    An exceptional surface-based sensor. The microring resonator is coupled to a waveguide with an end mirror that partially reflects light, which in turn enhances the sensitivity. Image Credit: Ramy El-Ganainy and Qi Zhong

    Tweaking the design of microring sensors enhances their sensitivity without adding more implementation complexity.

    Optical sensing is one of the most important applications of light science. It plays crucial roles in astronomy, environmental science, industry and medical diagnoses.

    Despite the variety of schemes used for optical sensing, they all share the same principle: The quantity to be measured must leave a “fingerprint” on the optical response of the system. The fingerprint can be its transmission, reflection or absorption. The stronger these effects are, the stronger the response of the system.

    While this works well at the macroscopic level, measuring tiny, microscopic quantities that induce weak response is a challenging task. Researchers have developed techniques to overcome this difficulty and improve the sensitivity of their devices. Some of these techniques, which rely on complex quantum optics concepts and implementations, have indeed proved useful, such as in sensing gravitational waves in the LIGO project.


    Others, which are based on trapping light in tiny boxes called optical resonators, have succeeded in detecting micro-particles and relatively large biological components.

    Nonetheless, the ability to detect small nano-particles and eventually single molecules remains a challenge. Current attempts focus on a special type of light trapping devices called microring or microtoroid resonators — these enhance the interaction between light and the molecule to be detected. The sensitivity of these devices, however, is limited by their fundamental physics.

    In their article “Sensing with Exceptional Surfaces in Order to Combine Sensitivity with Robustness” published in Physical Review Letters, physicists and engineers from Michigan Technological University, Pennsylvania State University and the University of Central Florida propose a new type of sensor. They are based on the new notion of exceptional surfaces: surfaces that consist of exceptional points.

    Exceptional Points for Exceptionally Sensitive Detection

    In order to understand the meaning of exceptional points, consider an imaginary violin with only two strings. In general, such a violin can produce just two different tones — a situation that corresponds to a conventional optical resonator. If the vibration of one string can alter the vibration of the other string in a way that the sound and the elastic oscillations create only one tone and one collective string motion, the system has an exceptional point.

    A physical system that exhibits an exceptional point is very fragile. In other words, any small perturbation will dramatically alter its behavior. The feature makes the system highly sensitive to tiny signals.

    “Despite this promise, the same enhanced sensitivity of exceptional point-based sensors is also their Achilles heel: These devices are very sensitive to unavoidable fabrication errors and undesired environmental variations,” said Ramy El-Ganainy, associate professor of physics, adding that the sensitivity necessitated clever tuning tricks in previous experimental demonstrations.

    “Our current proposal alleviates most of these problems by introducing a new system that has the same enhanced sensitivity reported in previous work, while at the same time robust against the majority of the uncontrivable experimental uncertainty,” said Qi Zhong, lead author on the paper and a graduate student who is currently working towards his doctorate degree at Michigan Tech.

    Though the design of microring sensors continues to be refined, researchers are hopeful that by improving the devices, seemingly tiny optical observations will have large effects.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Michigan Tech Campus
    Michigan Technological University (http://www.mtu.edu) is a leading public research university developing new technologies and preparing students to create the future for a prosperous and sustainable world. Michigan Tech offers more than 130 undergraduate and graduate degree programs in engineering; forest resources; computing; technology; business; economics; natural, physical and environmental sciences; arts; humanities; and social sciences.
    The College of Sciences and Arts (CSA) fills one of the most important roles on the Michigan Tech campus. We play a part in the education of every student who comes through our doors. We take pride in offering essential foundational courses in the natural sciences and mathematics, as well as the social sciences and humanities—courses that underpin every major on campus. With twelve departments, 28 majors, 30-or-so specializations, and more than 50 minors, CSA has carefully developed programs to suit many interests and skill sets. From sound design and audio technology to actuarial science, applied cognitive science and human factors to rhetoric and technical communication, the college offers many unique programs.

     
  • richardmitnick 9:09 am on May 13, 2019 Permalink | Reply
    Tags: , , , CLIC, , , , , Physics, Roadmap for the future of the discipline, The European Strategy Group   

    From CERN: “In Granada, the European particle physics community prepares decisions for the future of the field” 

    Cern New Bloc

    Cern New Particle Event


    From CERN

    13 May, 2019

    The European particle physics community is meeting this week in Granada, Spain, to discuss the roadmap for the future of the discipline.

    1

    Geneva and Granada. The European particle physics community is meeting this week in Granada, Spain, to discuss the roadmap for the future of the discipline. The aim of the symposium is to define scientific priorities and technological approaches for the coming years and to consider plans for the medium- and long-term future. An important focus of the discussions will be assessing the various options for the period beyond the lifespan of the Large Hadron Collider.

    “The Granada symposium is an important step in the process of updating the European Strategy for Particle Physics and aims to prioritise our scientific goals and prepare for the upcoming generation of facilities and experiments,” said the President of the CERN Council, Ursula Bassler. “The discussions will focus on the scientific reach of potential new projects, the associated technological challenges and the resources required.”

    The European Strategy Group, which was established to coordinate the update process, has received 160 contributions from the scientific community setting out their views on possible future projects and experiments. The symposium in Granada will provide an opportunity to assess and discuss them.

    “The intent is to make sure that we have a good understanding of the science priorities of the community and of all the options for realising them,” said the Chair of the European Strategy Group, Professor Halina Abramowicz. “This will ensure that the European Strategy Group is well informed when deciding about the strategy update.”

    The previous update of the European Strategy, approved in May 2013, recommended that design and feasibility studies be conducted in order for Europe “to be in a position to propose an ambitious post-LHC accelerator project.” Over the last few years, in collaboration with partners from around the world, Europe has therefore been engaging in R&D and design projects for a range of ambitious post-LHC facilities under the CLIC and FCC umbrellas.


    CLIC collider

    CERN FCC Future Circular Collider details of proposed 100km-diameter successor to LHC

    A study to investigate the potential to build projects that are complementary to high-energy colliders, exploiting the opportunities offered by CERN’s unique accelerator complex, was also launched by CERN in 2016. These contributions will feed into the discussion, which will also take into account the worldwide particle physics landscape and developments in related fields.

    “At least two decades will be needed to design and build a new collider to succeed the LHC. Such a machine should maximise the potential for new discoveries and enable major steps forward in our understanding of fundamental physics” said CERN Director-General, Fabiola Gianotti. “It is not too early to start planning for it as it will take time to develop the new technologies needed for its implementation.”

    The Granada symposium will be followed up with the compilation of a “briefing book” and with a Strategy Drafting Session, which will take place in Bad Honnef, Germany, from 20 to 24 January 2020. The update of the European Strategy for Particle Physics is due to be completed and approved by the CERN Council in May 2020.

    An online Q&A session will be held on Thursday 16 May – 4pm CEST

    Reporters interested in participating are invited to register by sending an e-mail to press@cern.ch

    https://europeanstrategy.cern/

    See the full article here.


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    Meet CERN in a variety of places:

    Quantum Diaries
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  • richardmitnick 11:56 am on May 12, 2019 Permalink | Reply
    Tags: "A Bizarre Form of Water May Exist All Over the Universe", , , Creating a shock wave that raised the water’s pressure to millions of atmospheres and its temperature to thousands of degrees., Experts say the discovery of superionic ice vindicates computer predictions which could help material physicists craft future substances with bespoke properties., Laboratory for Laser Energetics, Physics, Superionic ice, Superionic ice can now claim the mantle of Ice XVIII., Superionic ice is black and hot. A cube of it would weigh four times as much as a normal one., Superionic ice is either another addition to water’s already cluttered array of avatars or something even stranger., Superionic ice would conduct electricity like a metal with the hydrogens playing the usual role of electrons., The discovery of superionic ice potentially solves decades-old puzzles about the composition of “ice giant” worlds., The fields around the solar system’s other planets seem to be made up of strongly defined north and south poles without much other structure., The magnetic fields emanating from Uranus and Neptune looked lumpier and more complex with more than two poles., The probe Voyager 2 had sailed into the outer solar system uncovering something strange about the magnetic fields of the ice giants Uranus and Neptune., , What giant icy planets like Uranus and Neptune might be made of,   

    From University of Rochester Laboratory for Laser Energetics via WIRED: “A Bizarre Form of Water May Exist All Over the Universe” 

    U Rochester bloc

    From University of Rochester

    U Rochester’s Laboratory for Laser Energetics

    via

    Wired logo

    WIRED

    1
    The discovery of superionic ice potentially solves the puzzle of what giant icy planets like Uranus and Neptune are made of. They’re now thought to have gaseous, mixed-chemical outer shells, a liquid layer of ionized water below that, a solid layer of superionic ice comprising the bulk of their interiors, and rocky centers. Credit: @iammoteh/Quanta Magazine.

    Recently at the Laboratory for Laser Energetics in Brighton, New York, one of the world’s most powerful lasers blasted a droplet of water, creating a shock wave that raised the water’s pressure to millions of atmospheres and its temperature to thousands of degrees. X-rays that beamed through the droplet in the same fraction of a second offered humanity’s first glimpse of water under those extreme conditions.

    The X-rays revealed that the water inside the shock wave didn’t become a superheated liquid or gas. Paradoxically—but just as physicists squinting at screens in an adjacent room had expected—the atoms froze solid, forming crystalline ice.

    “You hear the shot,” said Marius Millot of Lawrence Livermore National Laboratory in California, and “right away you see that something interesting was happening.” Millot co-led the experiment with Federica Coppari, also of Livermore.

    The findings, published this week in Nature, confirm the existence of “superionic ice,” a new phase of water with bizarre properties. Unlike the familiar ice found in your freezer or at the north pole, superionic ice is black and hot. A cube of it would weigh four times as much as a normal one. It was first theoretically predicted more than 30 years ago, and although it has never been seen until now, scientists think it might be among the most abundant forms of water in the universe.

    Across the solar system, at least, more water probably exists as superionic ice—filling the interiors of Uranus and Neptune—than in any other phase, including the liquid form sloshing in oceans on Earth, Europa and Enceladus. The discovery of superionic ice potentially solves decades-old puzzles about the composition of these “ice giant” worlds.

    Including the hexagonal arrangement of water molecules found in common ice, known as “ice Ih,” scientists had already discovered a bewildering 18 architectures of ice crystal. After ice I, which comes in two forms, Ih and Ic, the rest are numbered II through XVII in order of their discovery. (Yes, there is an Ice IX, but it exists only under contrived conditions, unlike the fictional doomsday substance in Kurt Vonnegut’s novel Cat’s Cradle.)

    Superionic ice can now claim the mantle of Ice XVIII. It’s a new crystal, but with a twist. All the previously known water ices are made of intact water molecules, each with one oxygen atom linked to two hydrogens. But superionic ice, the new measurements confirm, isn’t like that. It exists in a sort of surrealist limbo, part solid, part liquid. Individual water molecules break apart. The oxygen atoms form a cubic lattice, but the hydrogen atoms spill free, flowing like a liquid through the rigid cage of oxygens.

    3
    A time-integrated photograph of the X-ray diffraction experiment at the University of Rochester’s Laboratory for Laser Energetics. Giant lasers focus on a water sample to compress it into the superionic phase. Additional laser beams generate an X-ray flash off an iron foil, allowing the researchers to take a snapshot of the compressed water layer. Credit: Millot, Coppari, Kowaluk (LLNL)

    Experts say the discovery of superionic ice vindicates computer predictions, which could help material physicists craft future substances with bespoke properties. And finding the ice required ultrafast measurements and fine control of temperature and pressure, advancing experimental techniques. “All of this would not have been possible, say, five years ago,” said Christoph Salzmann at University College London, who discovered ices XIII, XIV and XV. “It will have a huge impact, for sure.”

    Depending on whom you ask, superionic ice is either another addition to water’s already cluttered array of avatars or something even stranger. Because its water molecules break apart, said the physicist Livia Bove of France’s National Center for Scientific Research and Pierre and Marie Curie University, it’s not quite a new phase of water. “It’s really a new state of matter,” she said, “which is rather spectacular.”

    Puzzles Put on Ice

    Physicists have been after superionic ice for years—ever since a primitive computer simulation led by Pierfranco Demontis in 1988 predicted [Physical Review Letters] water would take on this strange, almost metal-like form if you pushed it beyond the map of known ice phases.

    Under extreme pressure and heat, the simulations suggested, water molecules break. With the oxygen atoms locked in a cubic lattice, “the hydrogens now start to jump from one position in the crystal to another, and jump again, and jump again,” said Millot. The jumps between lattice sites are so fast that the hydrogen atoms—which are ionized, making them essentially positively charged protons—appear to move like a liquid.

    This suggested superionic ice would conduct electricity, like a metal, with the hydrogens playing the usual role of electrons. Having these loose hydrogen atoms gushing around would also boost the ice’s disorder, or entropy. In turn, that increase in entropy would make this ice much more stable than other kinds of ice crystals, causing its melting point to soar upward.

    But all this was easy to imagine and hard to trust. The first models used simplified physics, hand-waving their way through the quantum nature of real molecules. Later simulations folded in more quantum effects but still sidestepped the actual equations required to describe multiple quantum bodies interacting, which are too computationally difficult to solve. Instead, they relied on approximations, raising the possibility that the whole scenario could be just a mirage in a simulation. Experiments, meanwhile, couldn’t make the requisite pressures without also generating enough heat to melt even this hardy substance.

    As the problem simmered, though, planetary scientists developed their own sneaking suspicions that water might have a superionic ice phase. Right around the time when the phase was first predicted, the probe Voyager 2 had sailed into the outer solar system, uncovering something strange about the magnetic fields of the ice giants Uranus and Neptune.

    The fields around the solar system’s other planets seem to be made up of strongly defined north and south poles, without much other structure. It’s almost as if they have just bar magnets in their centers, aligned with their rotation axes. Planetary scientists chalk this up to “dynamos”: interior regions where conductive fluids rise and swirl as the planet rotates, sprouting massive magnetic fields.

    By contrast, the magnetic fields emanating from Uranus and Neptune looked lumpier and more complex, with more than two poles. They also don’t align as closely to their planets’ rotation. One way to produce this would be to somehow confine the conducting fluid responsible for the dynamo into just a thin outer shell of the planet, instead of letting it reach down into the core.

    But the idea that these planets might have solid cores, which are incapable of generating dynamos, didn’t seem realistic. If you drilled into these ice giants, you would expect to first encounter a layer of ionic water, which would flow, conduct currents and participate in a dynamo. Naively, it seems like even deeper material, at even hotter temperatures, would also be a fluid. “I used to always make jokes that there’s no way the interiors of Uranus and Neptune are actually solid,” said Sabine Stanley at Johns Hopkins University. “But now it turns out they might actually be.”

    Ice on Blast

    Now, finally, Coppari, Millot and their team have brought the puzzle pieces together.

    In an earlier experiment, published last February [Nature Physics], the physicists built indirect evidence for superionic ice. They squeezed a droplet of room-temperature water between the pointy ends of two cut diamonds. By the time the pressure raised to about a gigapascal, roughly 10 times that at the bottom of the Marianas Trench, the water had transformed into a tetragonal crystal called ice VI. By about 2 gigapascals, it had switched into ice VII, a denser, cubic form transparent to the naked eye that scientists recently discovered also exists in tiny pockets inside natural diamonds.

    Then, using the OMEGA laser at the Laboratory for Laser Energetics, Millot and colleagues targeted the ice VII, still between diamond anvils. As the laser hit the surface of the diamond, it vaporized material upward, effectively rocketing the diamond away in the opposite direction and sending a shock wave through the ice. Millot’s team found their super-pressurized ice melted at around 4,700 degrees Celsius, about as expected for superionic ice, and that it did conduct electricity thanks to the movement of charged protons.

    4
    Federica Coppari, a physicist at Lawrence Livermore National Laboratory, with an x-ray diffraction image plate that she and her colleagues used to discover ice XVIII, also known as superionic ice. Credit: Eugene Kowaluk/Laboratory for Laser Energetics

    With those predictions about superionic ice’s bulk properties settled, the new study led by Coppari and Millot took the next step of confirming its structure. “If you really want to prove that something is crystalline, then you need X-ray diffraction,” Salzmann said.

    Their new experiment skipped ices VI and VII altogether. Instead, the team simply smashed water with laser blasts between diamond anvils. Billionths of a second later, as shock waves rippled through and the water began crystallizing into nanometer-size ice cubes, the scientists used 16 more laser beams to vaporize a thin sliver of iron next to the sample. The resulting hot plasma flooded the crystallizing water with X-rays, which then diffracted from the ice crystals, allowing the team to discern their structure.

    Atoms in the water had rearranged into the long-predicted but never-before-seen architecture, Ice XVIII: a cubic lattice with oxygen atoms at every corner and the center of each face. “It’s quite a breakthrough,” Coppari said.

    “The fact that the existence of this phase is not an artifact of quantum molecular dynamic simulations, but is real—­that’s very comforting,” Bove said.

    And this kind of successful cross-check behind simulations and real superionic ice suggests the ultimate “dream” of material physics researchers might be soon within reach. “You tell me what properties you want in a material, and we’ll go to the computer and figure out theoretically what material and what kind of crystal structure you would need,” said Raymond Jeanloz, a member of the discovery team based at University of California, Berkeley. “The community at large is getting close.”

    The new analyses also hint that although superionic ice does conduct some electricity, it’s a mushy solid. It would flow over time, but not truly churn. Inside Uranus and Neptune, then, fluid layers might stop about 8,000 kilometers down into the planet, where an enormous mantle of sluggish, superionic ice like Millot’s team produced begins. That would limit most dynamo action to shallower depths, accounting for the planets’ unusual fields.

    Other planets and moons in the solar system likely don’t host the right interior sweet spots of temperature and pressure to allow for superionic ice. But many ice giant-sized exoplanets might, suggesting the substance could be common inside icy worlds throughout the galaxy.

    Of course, though, no real planet contains just water. The ice giants in our solar system also mix in chemical species like methane and ammonia. The extent to which superionic behavior actually occurs in nature is “going to depend on whether these phases still exist when we mix water with other materials,” Stanley said. So far, that isn’t clear, although other researchers have argued [Science] superionic ammonia should also exist.

    Aside from extending their research to other materials, the team also hopes to keep zeroing in on the strange, almost paradoxical duality of their superionic crystals. Just capturing the lattice of oxygen atoms “is clearly the most challenging experiment I have ever done,” said Millot. They haven’t yet seen the ghostly, interstitial flow of protons through the lattice. “Technologically, we are not there yet,” Coppari said, “but the field is growing very fast.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    University of Rochester Laboratory for Laser Energetics

    The Laboratory for Laser Energetics (LLE) is a scientific research facility which is part of the University of Rochester’s south campus, located in Brighton, New York. The lab was established in 1970 and its operations since then have been funded jointly; mainly by the United States Department of Energy, the University of Rochester and the New York State government. The Laser Lab was commissioned to serve as a center for investigations of high-energy physics, specifically those involving the interaction of extremely intense laser radiation with matter. Many types of scientific experiments are performed at the facility with a strong emphasis on inertial confinement, direct drive, laser-induced fusion, fundamental plasma physics and astrophysics using OMEGA. In June of 1995, OMEGA became the world’s highest-energy ultraviolet laser. The lab shares its building with the Center for Optoelectronics and Imaging and the Center for Optics Manufacturing. The Robert L. Sproull Center for Ultra High Intensity Laser Research was opened in 2005 and houses the OMEGA EP laser, which was completed in May 2008.

    The laboratory is unique in conducting big science on a university campus.[not verified in body] More than 180 Ph.D.s have been awarded for research done at the LLE.[2][3] During summer months the lab sponsors a program for high school students which involves local-area high school juniors in the research being done at the laboratory. Most of the projects are done on current research that is led by senior scientists at the lab.

    U Rochester Campus

    The University of Rochester is one of the country’s top-tier research universities. Our 158 buildings house more than 200 academic majors, more than 2,000 faculty and instructional staff, and some 10,500 students—approximately half of whom are women.

    Learning at the University of Rochester is also on a very personal scale. Rochester remains one of the smallest and most collegiate among top research universities, with smaller classes, a low 10:1 student to teacher ratio, and increased interactions with faculty.

     
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