Tagged: Clean Energy Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 7:34 am on April 23, 2015 Permalink | Reply
    Tags: , , Clean Energy,   

    From ANU: “Australia can cut emissions and grow its economy” 

    ANU Australian National University Bloc

    Australian National University

    22 April 2015
    No Writer Credit

    1

    Australia can make deep cuts to its carbon emissions and move to full renewable energy for its electricity supply at a relatively low cost, an ANU report has found.

    The report, written by Associate Professor Frank Jotzo and PhD scholar Luke Kemp, reviews the evidence from major studies over the past eight years.

    It finds that the cost estimates for Australia reaching ambitious emissions reduction goals came down in every successive major report.

    “Deep cuts to Australia’s emissions can be achieved, at a low cost,” said Associate Professor Jotzo, director of the ANU Centre for Climate Economics and Policy at the Crawford School of Public Policy.

    Australia has committed to cut greenhouse gas emissions by five per cent of year 2000 levels by 2020, and is due in coming months to decide on emissions reduction targets for after 2020.

    Australia is among the world’s highest producers of per-capita carbon emissions, due to a heavy reliance on coal for electricity generation.

    Associate Professor Jotzo’s report, commissioned by WWF Australia (World Wildlife Fund), found the cost of moving to renewable energy was becoming cheaper, and strong climate action could be achieved while maintaining economic growth.

    “At the heart of a low-carbon strategy for Australia is a carbon-free power system,” he said.

    “Australia has among the best prerequisites in the world for moving to a fully renewable energy electricity supply.”

    He said the costs of carbon-free technology, such as wind and solar power, have fallen faster than expected.

    “For example, large-scale solar panel power stations are already only half the cost that the Treasury’s 2008 and 2011 modelling studies estimated they would be in the year 2030,” he said.

    The report is available at the WWF Australia website.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ANU Campus

    ANU is a world-leading university in Australia’s capital city, Canberra. Our location points to our unique history, ties to the Australian Government and special standing as a resource for the Australian people.

    Our focus on research as an asset, and an approach to education, ensures our graduates are in demand the world-over for their abilities to understand, and apply vision and creativity to addressing complex contemporary challenges.

     
  • richardmitnick 8:25 am on April 22, 2015 Permalink | Reply
    Tags: , , Clean Energy,   

    From Harvard: “A leap for ‘artificial leaf’” 

    Harvard University

    Harvard University

    April 21, 2015
    Peter Reuell

    New technique could open door to producing alternative-energy devices more cheaply

    1
    With support from Harvard President Drew Faust’s Climate Change Solutions Fund, Patterson Rockwood Professor of Energy Daniel Nocera and colleagues created an efficient method to harness the power of light to generate two powerful fuels. File photo by Rose Lincoln/Harvard Staff Photographer

    As an idea, the notion of an “artificial leaf” was always meant to be simple: Could scientists, using a handful of relatively cheap materials, harness the power of light to generate two powerful fuels — hydrogen and oxygen — by breaking apart water molecules?

    In practice, however, the idea faced a number of hurdles, including how to pattern the catalysts on silicon that would power the reaction. But that could soon change, says Patterson Rockwood Professor of Energy Daniel Nocera.

    Using an electro-chemical process similar to etching, Nocera and colleagues have developed a system of patterning that works in just minutes, as opposed to the weeks other techniques need.

    Dubbed reactive interface patterning promoted by lithographic electrochemistry, or RIPPLE, the process can be so tightly controlled that researchers can build photonic structures that control the light hitting the device and greatly increase its efficiency. The new system is described in two papers that appeared in recent weeks in the Journal of the American Chemical Society and the Proceedings of the National Academy of Sciences.

    “This is what I call frugal innovation,” Nocera said. “We called it RIPPLE because you can think of it like dropping a pebble in water that makes a pattern of ripples. This is really the simplest patterning technique that I know of. We take silicon, coat it with our catalyst, and within minutes we can pattern it using a standard electro-chemical technique we use in the lab.”

    The project was one of seven research efforts supported in the inaugural year of Harvard President Drew Faust’s Climate Change Solutions Fund. The $20 million fund was created to spur the development of renewable energy solutions and speed the transition from fossil fuels.

    “It’s already working,” Nocera said of the project. “We already have a home run, and that makes me very happy, because the idea we proposed actually works.”

    The ability to pattern catalysts — using cobalt phosphate to spur the creation of oxygen and a nickel-zinc alloy for hydrogen — on the silicon substrate is particularly important, Nocera said.

    “In our current system, we just have flat silicon and the catalyst is covering it, so the light has to come through the catalyst, and we have some energy loss,” he explained. “Using this, we are able to pattern the catalyst, so we have bare silicon in one location and the catalyst in another, so the light doesn’t have to go though the catalyst, making the system more efficient.”

    Equally important, Nocera said, the system allows for fast patterning of relatively large areas — far larger than other systems that use nano-scale patterning techniques.

    Ironically, the discovery of the technique came about almost by accident.

    “What we were trying to do was generate intense electrical fields to deposit the catalyst selectively on silicon,” Nocera explained. “It was during what was basically a control experiment that we noticed we didn’t need an intense electric field and could pattern the silicon quite easily.”

    While the mechanism at work in the patterning isn’t fully understood, Nocera and colleagues can maintain precise control over the process and produce everything from patterns of lines to rings to squares on silicon substrates.

    “It’s phenomenological. We don’t understand the mechanism yet,” Nocera said. “But we do understand how to control it, so we can fine-tune the spacing of the patterns, and what we’ve already produced can work for energy applications — with the catalyst and the artificial leaf, it’s remarkable.”

    See the full article here.

    Harvard is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s best known landmark.

    Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 3:52 pm on March 9, 2015 Permalink | Reply
    Tags: , , , Clean Energy,   

    From Caltech: “One Step Closer to Artificial Photosynthesis and “Solar Fuels” 

    Caltech Logo
    Caltech

    03/09/2015
    Ker Than

    1
    Ke Sun, a Caltech postdoc in the lab of George L. Argyros Professor and Professor of Chemistry Nate Lewis, peers into a sample of a new, protective film that he has helped develop to aid in the process of harnessing sunlight to generate fuels.
    Credit: Lance Hayashida/Caltech Marcomm

    Caltech scientists, inspired by a chemical process found in leaves, have developed an electrically conductive film that could help pave the way for devices capable of harnessing sunlight to split water into hydrogen fuel.

    When applied to semiconducting materials such as silicon, the nickel oxide film prevents rust buildup and facilitates an important chemical process in the solar-driven production of fuels such as methane or hydrogen.

    “We have developed a new type of protective coating that enables a key process in the solar-driven production of fuels to be performed with record efficiency, stability, and effectiveness, and in a system that is intrinsically safe and does not produce explosive mixtures of hydrogen and oxygen,” says Nate Lewis, the George L. Argyros Professor and professor of chemistry at Caltech and a coauthor of a new study, published the week of March 9 in the online issue of the journal the Proceedings of the National Academy of Sciences, that describes the film.

    The development could help lead to safe, efficient artificial photosynthetic systems—also called solar-fuel generators or “artificial leaves”—that replicate the natural process of photosynthesis that plants use to convert sunlight, water, and carbon dioxide into oxygen and fuel in the form of carbohydrates, or sugars.

    The artificial leaf that Lewis’ team is developing in part at Caltech’s Joint Center for Artificial Photosynthesis (JCAP) consists of three main components: two electrodes—a photoanode and a photocathode—and a membrane. The photoanode uses sunlight to oxidize water molecules to generate oxygen gas, protons, and electrons, while the photocathode recombines the protons and electrons to form hydrogen gas. The membrane, which is typically made of plastic, keeps the two gases separate in order to eliminate any possibility of an explosion, and lets the gas be collected under pressure to safely push it into a pipeline.

    Scientists have tried building the electrodes out of common semiconductors such as silicon or gallium arsenide—which absorb light and are also used in solar panels—but a major problem is that these materials develop an oxide layer (that is, rust) when exposed to water.

    Lewis and other scientists have experimented with creating protective coatings for the electrodes, but all previous attempts have failed for various reasons. “You want the coating to be many things: chemically compatible with the semiconductor it’s trying to protect, impermeable to water, electrically conductive, highly transparent to incoming light, and highly catalytic for the reaction to make oxygen and fuels,” says Lewis, who is also JCAP’s scientific director. “Creating a protective layer that displayed any one of these attributes would be a significant leap forward, but what we’ve now discovered is a material that can do all of these things at once.”

    The team has shown that its nickel oxide film is compatible with many different kinds of semiconductor materials, including silicon, indium phosphide, and cadmium telluride. When applied to photoanodes, the nickel oxide film far exceeded the performance of other similar films—including one that Lewis’s group created just last year. That film was more complicated—it consisted of two layers versus one and used as its main ingredient titanium dioxide (TiO2, also known as titania), a naturally occurring compound that is also used to make sunscreens, toothpastes, and white paint.

    “After watching the photoanodes run at record performance without any noticeable degradation for 24 hours, and then 100 hours, and then 500 hours, I knew we had done what scientists had failed to do before,” says Ke Sun, a postdoc in Lewis’s lab and the first author of the new study.

    Lewis’s team developed a technique for creating the nickel oxide film that involves smashing atoms of argon into a pellet of nickel atoms at high speeds, in an oxygen-rich environment. “The nickel fragments that sputter off of the pellet react with the oxygen atoms to produce an oxidized form of nickel that gets deposited onto the semiconductor,” Lewis says.

    Crucially, the team’s nickel oxide film works well in conjunction with the membrane that separates the photoanode from the photocathode and staggers the production of hydrogen and oxygen gases.

    “Without a membrane, the photoanode and photocathode are close enough to each other to conduct electricity, and if you also have bubbles of highly reactive hydrogen and oxygen gases being produced in the same place at the same time, that is a recipe for disaster,” Lewis says. “With our film, you can build a safe device that will not explode, and that lasts and is efficient, all at once.”

    Lewis cautions that scientists are still a long way off from developing a commercial product that can convert sunlight into fuel. Other components of the system, such as the photocathode, will also need to be perfected.

    “Our team is also working on a photocathode,” Lewis says. “What we have to do is combine both of these elements together and show that the entire system works. That will not be easy, but we now have one of the missing key pieces that has eluded the field for the past half-century.”

    Along with Lewis and Sun, additional authors on the paper, “Stable solar-driven oxidation of water by semiconducting photoanodes protected by transparent catalytic nickel oxide films,” include Caltech graduate students Fadl Saadi, Michael Lichterman, Xinghao Zhou, Noah Plymale, and Stefan Omelchenko; William Hale, from the University of Southampton; Hsin-Ping Wang and Jr-Hau He, from King Abdullah University in Saudi Arabia; Kimberly Papadantonakis, a scientific research manager at Caltech; and Bruce Brunschwig, the director of the Molecular Materials Research Center at Caltech. Funding was provided by the Office of Science at the U.S. Department of Energy, the National Science Foundation, the Beckman Institute, and the Gordon and Betty Moore Foundation.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”
    Caltech buildings

     
  • richardmitnick 7:24 am on February 17, 2015 Permalink | Reply
    Tags: , Clean Energy, , , ,   

    From physicsworld: “Smaller fusion reactors could deliver big gains” 

    physicsworld
    physicsworld.com

    Feb 16, 2015
    Michael Banks

    1
    Hot topic: size may not be everything in tokamak design

    Researchers from the UK firm Tokamak Energy say that future fusion reactors could be made much smaller than previously envisaged – yet still deliver the same energy output. That claim is based on calculations showing that the fusion power gain – a measure of the ratio of the power from a fusion reactor to the power required to maintain the plasma in steady state – does not depend strongly on the size of the reactor. The company’s finding goes against conventional thinking, which says that a large power output is only possible by building bigger fusion reactors.

    The largest fusion reactor currently under construction is the €16bn ITER facility in Cadarache, France.

    ITER Tokamak

    This will weigh about 23,000 tonnes when completed in the coming decade and consist of a deuterium–tritium plasma held in a 60 m-tall, doughnut-shaped “tokamak”. ITER aims to produce a fusion power gain (Q) of 10, meaning that, in theory, the reactor will emit 10 times the power it expends by producing 500 MW from 50 MW of input power. While ITER has a “major” plasma radius of 6.21 m, it is thought that an actual future fusion power plant delivering power to the grid would need a 9 m radius to generate 1 GW.

    Low power brings high performance

    The new study, led by Alan Costley from Tokamak Energy, which builds compact tokamaks, shows that smaller, lower-power, and therefore lower-cost reactors could still deliver a value of Q similar to ITER. The work focused on a key parameter in determining plasma performance called the plasma “beta”, which is the ratio of the plasma pressure to the magnetic pressure. By using scaling expressions consistent with existing experiments, the researchers show that the power needed for high fusion performance can be three or four times lower than previously thought.

    Combined with the finding on the size-dependence of Q, these results imply the possibility of building lower-power, smaller and cheaper pilot plants and reactors. “The consequence of beta-independent scaling is that tokamaks could be much smaller, but still have a high power gain,” David Kingham, Tokamak Energy chief executive, told Physics World.

    The researchers propose that a reactor with a radius of just 1.35 m would be able to generate 180 MW, with a Q of 5. This would result in a reactor just 1/20th of the size of ITER. “Although there are still engineering challenges to overcome, this result is underpinned by good science,” says Kingham. “We hope that this work will attract further investment in fusion energy.”

    Many challenges remain

    Howard Wilson, director of the York Plasma Institute at the University of York in the UK, points out, however, that the result relies on being able to achieve a very high magnetic field. “We have long been aware that a high magnetic field enables compact fusion devices – the breakthrough would be in discovering how to create such high magnetic fields in the tokamak,” he says. “A compact fusion device may indeed be possible, provided one can achieve high confinement of the fuel, demonstrate efficient current drive in the plasma, exhaust the heat and particles effectively without damaging material surfaces, and create the necessary high magnetic fields.”

    The work by Tokamak Energy follows an announcement late last year that the US firm Lockheed Martin plans to build a “truck-sized” compact fusion reactor by 2019 that would be capable of delivering 100 MW. However, the latest results from Tokamak Energy might not be such bad news for ITER. Kingham adds that his firm’s work means that, in principle, ITER is actually being built much larger than necessary – and so should outperform its Q target of 10.

    The research is published in Nuclear Fusion.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    PhysicsWorld is a publication of the Institute of Physics. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application.

    We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications.
    IOP Institute of Physics

     
  • richardmitnick 1:17 pm on February 6, 2015 Permalink | Reply
    Tags: , Clean Energy, , Wave and tidal energy   

    From U Washington: “New tool monitors effects of tidal, wave energy on marine habitat” 

    U Washington

    University of Washington

    February 5, 2015
    Michelle Ma, News and Information

    Researchers building a new underwater robot they’ve dubbed the “Millennium Falcon” certainly have reason to believe it will live up to its name.

    1
    From left to right: UW researchers Ben Rush, Nick Michel-Hart, James Joslin and Paul Gibbs prepare to test the monitoring device underwater in a tank on campus.
    Applied Physics Laboratory, UW

    The robot will deploy instruments to gather information in unprecedented detail about how marine life interacts with underwater equipment used to harvest wave and tidal energy. Researchers still don’t fully understand how animals and fish will be affected by ocean energy equipment, and this instrument seeks to identify risks that could come into play in a long-term marine renewable energy project.

    “This is the first attempt at a ‘plug-and-socket’ instrumentation package in the marine energy field. If successful, it will change the way that industry views the viability of environmental research and development,” said Brian Polagye, a University of Washington assistant professor of mechanical engineering and one of the project’s leaders.

    2
    The Millennium Falcon robot maneuvers underwater in a testing tank on campus. The monitoring instruments (white box in the middle) are guided by the robot’s thrusters toward a docking station on the bottom of the tank. Researchers controlled the machine from above.Applied Physics Laboratory, UW

    The UW research team tested the Millennium Falcon and the instruments it transports, called the Adaptable Monitoring Package, underwater for the first time in January in a deep tank on campus. Researchers will continue testing in Puget Sound under more challenging conditions starting this month. They hope this tool will be useful for pilot tidal- and wave-energy projects and eventually in large-scale, commercial renewable-energy projects.

    “We’ve really become leaders in this space, leveraging UW expertise with cabled instrumentation packages like those developed for the Ocean Observatories Initiative. What’s novel here is the serviceability of the system and our ability to rapidly deploy and recover the instruments at low cost,” said Andrew Stewart, an ocean engineer at the UW Applied Physics Laboratory.

    The instrument package can track and measure a number of sights and sounds underwater. It has a stereo camera to collect photos and video, a sonar system, hydrophones to hear marine mammal activity, sensors to gauge water quality and speed, a click detector to listen for whales, dolphins and porpoises, and even a device to detect fish tags. A fiber optic cable connection back to shore allows for real-time monitoring and control, and the device will be powered by a copper wire.

    The breadth of sensors and various conditions this instrument can measure is unprecedented, researchers say. The tool also is unique for its ability to attach to most types of underwater infrastructure, ranging from tidal turbines to offshore oil and gas rigs. This allows researchers to easily deploy the instrument far offshore and recover it quickly at a relatively low cost compared with other approaches.

    “It could be a first step toward a standardized ‘science port’ for marine energy projects,” Polagye said.

    This speedy deployment and recovery — sometimes in rough seas — is possible because the instrument fits inside a remotely operated vehicle, or ROV, that can maneuver underwater and drop off the instrumentation package at a docking station integrated onto a turbine or other existing subsea infrastructure.
    The monitoring instruments are housed inside the white box in the middle. The Millennium Falcon ROV is positioned just over and under the white box. Researchers tested the device’s ability to fasten onto a docking station underwater, seen foreground.

    The monitoring instruments are housed inside the white box in the middle. The Millennium Falcon ROV is positioned just over and under the white box. Researchers tested the device’s ability to fasten onto a docking station underwater, seen foreground.Applied Physics Laboratory, UW

    The vehicle is about the size of a golf cart, and the research team outfitted the off-the-shelf Falcon underwater surveying machine with five extra thrusters on an external frame to give it more power to move against strong currents. Actuators on the vehicle latch the monitoring instruments onto a subsea docking station, and then the Millennium Falcon can disengage, leaving the instruments in place, and travel back to the water’s surface.

    The shape of the monitoring package resembles an X-wing Starfighter from the original “Star Wars” trilogy. (The researchers are mum on whether their Millennium Falcon can make the Kessel Run in less than 12 parsecs.)

    This project is a collaboration between researchers in mechanical engineering and the Applied Physics Laboratory, within the larger Northwest National Marine Renewable Energy Center, which is a multi-institution organization that develops marine renewable energy technologies through research, education and outreach. The center and the Applied Physics Laboratory recently received $8 million from the U.S. Navy to develop marine renewable energy for use at its facilities worldwide.

    Development of this environmental monitoring instrument was prompted by a long-running tidal energy pilot project with the Snohomish County Public Utility District in Admiralty Inlet that recently was dropped because of ballooning costs. Going forward, researchers expect to use the same device to monitor marine-energy projects cropping up around the world and help to reduce the cost of future developments.

    “Snohomish PUD was really at the forefront of projects grappling with this problem of monitoring a tidal turbine in deep, fast moving water. But as other projects in the U.S., Europe and Canada have faced similar monitoring scenarios, the instrumentation package is shaping up as a strong candidate to meet their needs,” Polagye said.

    Other lead researchers are UW mechanical engineering graduate students James Joslin and Emma Cotter.

    The project is funded by the U.S. Department of Energy, the U.S. Naval Facilities Engineering Command, the Snohomish County Public Utility District and the UW.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.

    So what defines us — the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

     
  • richardmitnick 8:20 am on January 30, 2015 Permalink | Reply
    Tags: , Clean Energy, , , Solar Fuels   

    From Science 2.0: “Calculating The Future Of Solar-fuel Refineries” 

    Science 2.0 bloc

    Science 2.0

    January 30th 2015
    News Staff

    The process of converting the sun’s energy into liquid fuels requires a sophisticated, interrelated series of choices but a solar refinery is especially tricky to map out because the designs involve newly developed or experimental technologies. This makes it difficult to develop realistic plans that are economically viable and energy efficient.

    In a paper recently published in the journal Energy & Environmental Science, a team led by University of Wisconsin-Madison chemical and biological engineering Professors Christos Maravelias and George Huber outlined a tool to help engineers better gauge the overall yield, efficiency and costs associated with scaling solar-fuel production processes up into large-scale refineries.

    1

    That’s where the new UW-Madison tool comes in. It’s a framework that focuses on accounting for general variables and big-picture milestones associated with scaling up energy technologies to the refinery level. This means it’s specifically designed to remain relevant even as solar-fuel producers and researchers experiment with new technologies and ideas for technologies that don’t yet exist.

    Renewable-energy researchers at UW-Madison have long emphasized the importance of considering energy production as a holistic process, and Maravelias says the new framework could be used by a wide range of solar energy stakeholders, from basic science researchers to business decision-makers. The tool could also play a role in wider debates about which renewable-energy technologies are most appropriate for society to pursue on a large scale.

    “The nice thing about it being general is that if a researcher develops a different technology – and there are many different ways to generate solar fuels – our framework would still be applicable, and if someone wants a little more detail, our framework can be adjusted accordingly,” Maravelias says.

    In addition to bringing clarity to the solar refinery conversation, the framework could also be adapted to help analyze and plan any number of other energy-related processes, says Jeff Herron, a postdoc in Maravelias’ group and the paper’s lead author.

    “People tend to be narrowly focused on their particular role within a bigger picture,” Herron says. “I think bringing all that together is unique to our work, and I think that’s going to be one of the biggest impacts.”

    Ph.D. student Aniruddha Upadhye and postdoc Jiyong Kim also contributed to the project. The research was funded by the U.S. Department of Energy.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 3:17 pm on January 23, 2015 Permalink | Reply
    Tags: , , Clean Energy, , ,   

    From BNL: “Self-Assembled Nanotextures Create Antireflective Surface on Silicon Solar Cells” 

    Brookhaven Lab

    January 21, 2015
    Karen McNulty Walsh, (631) 344-8350 or Peter Genzer, (631) 344-3174

    Nanostructured surface textures—with shapes inspired by the structure of moths’ eyes—prevent the reflection of light off silicon, improving conversion of sunlight to electricity

    1
    Chuck Black of the Center for Functional Nanomaterials displays a nanotextured square of silicon on top of an ordinary silicon wafer. The nanotextured surface is completely antireflective and could boost the production of solar energy from silicon solar cells.

    Reducing the amount of sunlight that bounces off the surface of solar cells helps maximize the conversion of the sun’s rays to electricity, so manufacturers use coatings to cut down on reflections. Now scientists at the U.S. Department of Energy’s Brookhaven National Laboratory show that etching a nanoscale texture onto the silicon material itself creates an antireflective surface that works as well as state-of-the-art thin-film multilayer coatings.

    The surface nanotexture … drastically cut down on reflection of many wavelengths of light simultaneously.

    Their method, described in the journal Nature Communications and submitted for patent protection, has potential for streamlining silicon solar cell production and reducing manufacturing costs. The approach may find additional applications in reducing glare from windows, providing radar camouflage for military equipment, and increasing the brightness of light-emitting diodes.

    “For antireflection applications, the idea is to prevent light or radio waves from bouncing at interfaces between materials,” said physicist Charles Black, who led the research at Brookhaven Lab’s Center for Functional Nanomaterials (CFN), a DOE Office of Science User Facility.

    Preventing reflections requires controlling an abrupt change in “refractive index,” a property that affects how waves such as light propagate through a material. This occurs at the interface where two materials with very different refractive indices meet, for example at the interface between air and silicon. Adding a coating with an intermediate refractive index at the interface eases the transition between materials and reduces the reflection, Black explained.

    “The issue with using such coatings for solar cells,” he said, “is that we’d prefer to fully capture every color of the light spectrum within the device, and we’d like to capture the light irrespective of the direction it comes from. But each color of light couples best with a different antireflection coating, and each coating is optimized for light coming from a particular direction. So you deal with these issues by using multiple antireflection layers. We were interested in looking for a better way.”

    For inspiration, the scientists turned to a well-known example of an antireflective surface in nature, the eyes of common moths. The surfaces of their compound eyes have textured patterns made of many tiny “posts,” each smaller than the wavelengths of light. This textured surface improves moths’ nighttime vision, and also prevents the “deer in the headlights” reflecting glow that might allow predators to detect them.

    “We set out to recreate moth eye patterns in silicon at even smaller sizes using methods of nanotechnology,” said Atikur Rahman, a postdoctoral fellow working with Black at the CFN and first author of the study.

    2
    A closeup shows how the nanotextured square of silicon completely blocks reflection compared with the surrounding silicon wafer.

    The scientists started by coating the top surface of a silicon solar cell with a polymer material called a “block copolymer,” which can be made to self-organize into an ordered surface pattern with dimensions measuring only tens of nanometers. The self-assembled pattern served as a template for forming posts in the solar cell like those in the moth eye using a plasma of reactive gases—a technique commonly used in the manufacture of semiconductor electronic circuits.

    The resulting surface nanotexture served to gradually change the refractive index to drastically cut down on reflection of many wavelengths of light simultaneously, regardless of the direction of light impinging on the solar cell.

    “Adding these nanotextures turned the normally shiny silicon surface absolutely black,” Rahman said.

    Solar cells textured in this way outperform those coated with a single antireflective film by about 20 percent, and bring light into the device as well as the best multi-layer-coatings used in the industry.

    “We are working to understand whether there are economic advantages to assembling silicon solar cells using our method, compared to other, established processes in the industry,” Black said.

    Hidden layer explains better-than-expected performance

    One intriguing aspect of the study was that the scientists achieved the antireflective performance by creating nanoposts only half as tall as the required height predicted by a mathematical model describing the effect. So they called upon the expertise of colleagues at the CFN and other Brookhaven scientists to help sort out the mystery.

    3
    Details of the nanotextured antireflective surface as revealed by a scanning electron microscope at the Center for Functional Nanomaterials. The tiny posts, each smaller than the wavelengths of light, are reminiscent of the structure of moths’ eyes, an example of an antireflective surface found in nature.

    “This is a powerful advantage of doing research at the CFN—both for us and for academic and industrial researchers coming to use our facilities,” Black said. “We have all these experts around who can help you solve your problems.”

    Using a combination of computational modeling, electron microscopy, and surface science, the team deduced that a thin layer of silicon oxide similar to what typically forms when silicon is exposed to air seemed to be having an outsized effect.

    “On a flat surface, this layer is so thin that its effect is minimal,” explained Matt Eisaman of Brookhaven’s Sustainable Energy Technologies Department and a professor at Stony Brook University. “But on the nanopatterned surface, with the thin oxide layer surrounding all sides of the nanotexture, the oxide can have a larger effect because it makes up a significant portion of the nanotextured material.”

    Said Black, “This ‘hidden’ layer was the key to the extra boost in performance.”

    The scientists are now interested in developing their self-assembly based method of nanotexture patterning for other materials, including glass and plastic, for antiglare windows and coatings for solar panels.

    This research was supported by the DOE Office of Science.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

     
  • richardmitnick 8:36 pm on December 8, 2014 Permalink | Reply
    Tags: , Clean Energy, , , ,   

    From PPPL: “Monumental effort: How a dedicated team completed a massive beam-box relocation for the NSTX upgrade” 


    PPPL

    December 8, 2014
    By John Greenwald

    Your task: Take apart, decontaminate, refurbish, relocate, reassemble, realign and reinstall a 75-ton neutral beam box that will add a second beam box to the National Spherical Torus Experiment-Upgrade (NSTX-U) and double the experiment’s heating power. Oh, and while you’re at it, hoist the two-story tall box over a 22-foot wall.

    Members of the “Beam Team” faced those challenges when moving the huge box from the Tokamak Fusion Test Reactor (TFTR) cell to the NSTX-U cell. The task required all the savvy of the PPPL engineers and technicians who make up the veteran team. “They’re a tight-knit group that really knows what they’re doing,” said Mike Williams, director of engineering and infrastructure and associate director of PPPL and a former member of the team himself.

    The second box is one of the two major components of the upgrade that will make NSTX-U the most powerful spherical tokamak fusion facility in the world when construction is completed early next year. The new center stack that serves as the other component will double the strength and duration of the magnetic field that controls the plasma that fuels fusion reactions.

    The two new components will work together hand-in-glove. The stronger magnetic field will increase the confinement time for the plasma while the second beam box performs double-duty. Its beams will raise the temperature of the plasma and will help to maintain a current in the plasma to demonstrate that future tokamaks can operate in a continuous condition known as a “steady state.” The second box is “an absolutely crucial part of the upgrade,” said Masayuki Ono, project director for the NSTX-U.

    PPPL Tokamak
    PPPL Tokamak

    Work began in 2009

    Work on the second beam box began in 2009 when technicians clad in protective clothing dismantled and decontaminated the box as it sat in the TFTR test cell. While the box had used radioactive tritium to heat the plasma in TFTR, no tritium will be used in NSTX-U experiments.

    The decontamination took huge effort, said Tim Stevenson, who led the beam box project. Workers wearing protective garb used cloths, Windex and sprayers with deionized water to clean every part of the box by hand, and went over each part as many as 50 separate times. The cloths were then packaged and shipped to a Utah radiation-waste disposal site.

    Next came the task of moving the beam box and its cleaned and refurbished components out of the TFTR area and into the NSTX-U test cell next door. But how do you get something so massive to budge?

    The Beam Team solved the problem with air casters, said Ron Strykowsky, who heads the NSTX-U upgrade program. Using a ceiling crane, workers lifted the box onto the casters, which floated the load on a cushion of air just above the floor, enabling forklifts to tow it. Technicians then removed some hardware from the large doorway between the two test cells so the beam box could get through.

    The doorway led to a section of the NSTX-U area that is separated from the vacuum vessel by a 22-foot shield wall — a barrier too high for the box and its lid to clear when suspended by sling from a crane. Workers surmounted the problem by first lifting the box and then the lid, which had been removed during the decontamination process. The parts cleared the wall and sailed over the vacuum vessel before coming to rest on the test cell floor. The vessel itself was wrapped in plastic to prevent contamination from any tritium that might still be in the box and the lid as they swung by overhead.

    “Like rebuilding a ship in a bottle”

    The beam box was now ready to be reassembled and reinstalled. But carving out room for all the parts and equipment, including power supplies, cables, and cooling water pipes, proved difficult. “There were so many conflicting demands for space that it was like rebuilding a ship in a bottle,” Stevenson said, citing a remark originally made by engineer Larry Dudek, who heads the center stack upgrade project. “There was no existing footprint,” Stevenson said. “We had to make our own footprint.”

    Technicians needed to cut a port into the vacuum vessel for the beam to pass through. But the supplier-built unit that connected the box to the vessel left too much space between the unit and this new port, requiring the Welding Shop to fill in the gap. “The Welding Shop saved the port,” Stevenson said.

    Still another challenge called for ensuring that the beam would enter the plasma at precisely the angle that NSTX-U specifications required. Complicating this task was the test cell’s uneven floor, which meant that the position of the box also had to be adjusted. To align the beam, engineers used measurements to derive a bull’s-eye on the inside of the vessel; technicians then used laser technology to zero in on the target. The joint effort aligned the beam to within 80 thousands of an inch of the target.

    Installing power supplies

    Left to complete was installation of power supplies, a task accomplished earlier this year. The job called for bringing three orange high-voltage enclosures — the source of the power — up from a basement area and into the test cell through a hatch in the floor. Taken together, the two NSTX-U beam boxes will have the capacity to put up to 18 megawatts of power into the plasma, enough to briefly light some 20,000 homes.

    When asked to name the greatest challenge the project encountered, Stevenson replied, “The whole thing was fraught with challenges and difficulties. It was a monumental team effort that took a great deal of preparation. And when it was show-time, everyone showed up.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

     
  • richardmitnick 6:01 pm on November 26, 2014 Permalink | Reply
    Tags: , , Clean Energy, ,   

    From Caltech: “New Technique Could Harvest More of the Sun’s Energy” 

    Caltech Logo
    Caltech

    11/26/2014
    Jessica Stoller-Conrad

    As solar panels become less expensive and capable of generating more power, solar energy is becoming a more commercially viable alternative source of electricity. However, the photovoltaic cells now used to turn sunlight into electricity can only absorb and use a small fraction of that light, and that means a significant amount of solar energy goes untapped.

    A new technology created by researchers from Caltech, and described in a paper published online in the October 30 issue of Science Express, represents a first step toward harnessing that lost energy.

    m
    An ultra-sensitive needle measures the voltage that is generated while the nanospheres are illuminated.
    Credit: AMOLF/Tremani – Figure: Artist impression of the plasmo-electric effect.

    Sunlight is composed of many wavelengths of light. In a traditional solar panel, silicon atoms are struck by sunlight and the atoms’ outermost electrons absorb energy from some of these wavelengths of sunlight, causing the electrons to get excited. Once the excited electrons absorb enough energy to jump free from the silicon atoms, they can flow independently through the material to produce electricity. This is called the photovoltaic effect—a phenomenon that takes place in a solar panel’s photovoltaic cells.

    Although silicon-based photovoltaic cells can absorb light wavelengths that fall in the visible spectrum—light that is visible to the human eye—longer wavelengths such as infrared light pass through the silicon. These wavelengths of light pass right through the silicon and never get converted to electricity—and in the case of infrared, they are normally lost as unwanted heat.

    “The silicon absorbs only a certain fraction of the spectrum, and it’s transparent to the rest. If I put a photovoltaic module on my roof, the silicon absorbs that portion of the spectrum, and some of that light gets converted into power. But the rest of it ends up just heating up my roof,” says Harry A. Atwater, the Howard Hughes Professor of Applied Physics and Materials Science; director, Resnick Sustainability Institute, who led the study.

    Now, Atwater and his colleagues have found a way to absorb and make use of these infrared waves with a structure composed not of silicon, but entirely of metal.

    The new technique they’ve developed is based on a phenomenon observed in metallic structures known as plasmon resonance. Plasmons are coordinated waves, or ripples, of electrons that exist on the surfaces of metals at the point where the metal meets the air.

    While the plasmon resonances of metals are predetermined in nature, Atwater and his colleagues found that those resonances are capable of being tuned to other wavelengths when the metals are made into tiny nanostructures in the lab.

    “Normally in a metal like silver or copper or gold, the density of electrons in that metal is fixed; it’s just a property of the material,” Atwater says. “But in the lab, I can add electrons to the atoms of metal nanostructures and charge them up. And when I do that, the resonance frequency will change.”

    “We’ve demonstrated that these resonantly excited metal surfaces can produce a potential”—an effect very similar to rubbing a glass rod with a piece of fur: you deposit electrons on the glass rod. “You charge it up, or build up an electrostatic charge that can be discharged as a mild shock,” he says. “So similarly, exciting these metal nanostructures near their resonance charges up those metal structures, producing an electrostatic potential that you can measure.”

    This electrostatic potential is a first step in the creation of electricity, Atwater says. “If we can develop a way to produce a steady-state current, this could potentially be a power source. He envisions a solar cell using the plasmoelectric effect someday being used in tandem with photovoltaic cells to harness both visible and infrared light for the creation of electricity.

    Although such solar cells are still on the horizon, the new technique could even now be incorporated into new types of sensors that detect light based on the electrostatic potential.

    “Like all such inventions or discoveries, the path of this technology is unpredictable,” Atwater says. “But any time you can demonstrate a new effect to create a sensor for light, that finding has almost always yielded some kind of new product.”

    This work was published in a paper titled, Plasmoelectric Potentials in Metal Nanostructures. Other coauthors include first author Matthew T. Sheldon, a former postdoctoral scholar at Caltech; Ana M. Brown, an applied physics graduate student at Caltech; and Jorik van de Groep and Albert Polman from the FOM Institute AMOLF in Amsterdam. The study was funded by the Department of Energy, the Netherlands Organization for Scientific Research, and an NSF Graduate Research Fellowship.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”
    Caltech buildings

     
  • richardmitnick 2:29 pm on November 11, 2014 Permalink | Reply
    Tags: , Clean Energy, , ,   

    From PPPL: “PPPL researchers present cutting edge results at APS Plasma Physics Conference” 


    PPPL

    November 10, 2014
    Kitta MacPherson
    Email: kittamac@pppl.gov
    Phone: 609-243-2755

    Some 135 researchers, graduate students, and staff members from PPPL joined 1,500 research scientists from around the world at the 56th annual meeting of the American Physical Society Division of Plasma Physics Conference from Oct. 27 to Oct. 31 in New Orleans. Topics in the sessions ranged from waves in plasma to the physics of ITER, the international physics experiment in Cadarache, France; to women in plasma physics. Dozens of PPPL scientists presented the results of their cutting-edge research into magnetic fusion and plasma science. There were about 100 invited speakers at the conference, more than a dozen of whom were from PPPL.

    sw
    Conceptual image of the solar wind from the sun encountering the Earth’s magnetosphere. No image credit

    The press releases in this issue are condensed versions of press releases that were prepared by the APS with the assistance of the scientists quoted and with background material written by John Greenwald and Jeanne Jackson DeVoe. The full text is available at the APS Virtual Pressroom 2014: http://www.aps.org/units/dpp/meetings/vpr/2014/index.cfm.

    How magnetic reconnection goes “Boom!”

    MRX research reveals how magnetic energy turns into explosive particle energy

    Paper by: M. Yamada, J. Yoo

    Magnetic reconnection, in which the magnetic field lines in plasma snap apart and violently reconnect, creates massive eruptions of plasma from the sun. But how reconnection transforms magnetic energy into explosive particle energy has been a major mystery.

    Now research conducted on the Magnetic Reconnection Experiment (MRX) at PPPL has taken a key step toward identifying how the transformation takes place, and measuring experimentally the amount of magnetic energy that turns into particle energy. The investigation showed that reconnection in a prototypical reconnection layer converts about 50 percent of the magnetic energy, with one-third of the conversion heating the electrons and two-thirds accelerating the ion in the plasma.

    “This is a major milestone for our research,” said Masaaki Yamada, the principal investigator for the MRX. “We can now see the entire picture of how much of the energy goes to the electrons and how much to the ions in a prototypical reconnection layer.”

    What a Difference a Magnetic Field Makes

    Experiments on MRX confirm the lack of symmetry in converging space plasmas

    Paper by: J. Yoo

    Spacecraft observing magnetic reconnection have noted a fundamental gap between most theoretical studies of the phenomenon and what happens in space. While the studies assume that the converging plasmas share symmetrical characteristics such as temperature, density and magnetic strength, observations have shown that this is hardly the case.

    PPPL researchers have now found the disparity in plasma density in experiments conducted on the MRX. The work, done in collaboration with the Space Science Center at the University of New Hampshire, marks the first laboratory confirmation of the disparity and deepens understanding of the mechanisms involved.

    Data from the MRX findings could help to inform a four-satellite mission—the Magnetospheric Multiscale Mission, or MMS—that NASA plans to launch next year to study reconnection in the magnetosphere. The probes could produce a better understanding of geomagnetic storms and lead to advanced warning of the disturbances and an improved ability to cope with them.

    Using radio waves to control density in fusion plasma

    Experiments show how heating electrons in the center of hot fusion plasma can increase turbulence, reducing the density in the inner core

    Paper by: D. Ernst, K. Burrell, W. Guttenfelder, T. Rhodes, A. Dimits

    Recent fusion experiments on the DIII-D tokamak at General Atomics in San Diego and the Alcator C-Mod tokamak at MIT show that beaming microwaves into the center of the plasma can be used to control the density in the center of the plasma. The experiments and analysis were conducted by a team of researchers as part of a National Fusion Science Campaign.

    The new experiments reveal that turbulent density fluctuations in the inner core intensify when most of the heat goes to electrons instead of plasma ions, as would happen in the center of a self-sustaining fusion reaction. Supercomputer simulations closely reproduce the experiments, showing that the electrons become more turbulent as they are more strongly heated, and this transports both particles and heat out of the plasma.

    “As we approached conditions where mainly the electrons are heated, pure trapped electrons begin to dominate,” said Walter Guttenfelder, who did the supercomputer simulations for the DIII-D experiments along with Andris Dimits of Lawrence Livermore National Laboratory. Guttenfelder was a co-leader of the experiments and simulations with Keith Burrell of General Atomics and Terry Rhoades of UCLA. Darin Ernst of MIT led the overall research.

    Calming the Plasma Edge: The Tail that Wags the Dog

    Lithium injections show promise for optimizing the performance of fusion plasmas

    Paper by: G.L. Jackson, R. Maingi, T. Osborne, Z. Yan, D. Mansfield, S.L. Allen

    Experiments on the DIII-D tokamak fusion reactor that General Atomics operates for the U.S. Department of Energy have demonstrated the ability of lithium injections to transiently double the temperature and pressure at the edge of the plasma and delay the onset of instabilities and other transients. Researchers conducted the experiments using a lithium-injection device developed at PPPL.

    Lithium can play an important role in controlling the edge region and hence the evolution of the entire plasma. In the present work, lithium diminished the frequency of instabilities known as “edge localized modes” (ELMs), which have associated heat pulses that can damage the section of the vessel wall used to exhaust heat in fusion devices.

    The tailored injections produced ELM-free periods of up to 0.35 seconds, while reference discharges without lithium showed no ELM-free periods above 0.03 sec. The lithium rapidly increased the width of the pedestal region—the edge of the plasma where temperature drops off sharply—by up to 100 percent and raised the electron pressure and total pressure in the edge by up to 100 percent and 60 percent respectively. These dramatic effects produced a 60 percent increase in total energy-confinement time.

    Scratching the surface of a material mystery

    Scientists shed new light on how lithium conditions the volatile edge of fusion plasmas

    Paper by: Angela Capece

    For fusion energy to fuel future power plants, scientists must find ways to control the interactions that take place between the volatile edge of fusion plasma and the physical walls that surround it in fusion facilities. Such interactions can profoundly affect conditions at the superhot core of the plasma in ways that include kicking up impurities that cool down the core and halt fusion reactions. Among the puzzles is how temperature affects the ability of lithium to absorb and retain the deuterium particles that stray from the fuel that creates fusion reactions.

    Answers are now emerging from a new surface-science laboratory at PPPL that can probe lithium coatings that are just three atoms thick. The experiments showed that the ability of ultrathin lithium films to retain deuterium drops as the temperature of the molybdenum substrate rises—a result that provides insight into how lithium affects the performance of tokamaks

    Experiments further showed that exposing the lithium to oxygen improved deuterium retention at temperatures below about 400 degrees Kelvin. But without exposure to oxygen, lithium films could retain deuterium at higher temperatures as a result of lithium-deuterium bonding during a PPPL experiment.

    Putting Plasma to Work Upgrading the U.S. Power Grid

    PPPL lends GE a hand in developing an advanced power-conversion switch

    Paper by: Johan Carlsson, Alex Khrabrov, Igor Kaganovich, Timothy Summerer

    When researchers at General Electric sought help in designing a plasma-based power switch, they turned to PPPL. The proposed switch, which GE is developing under contract with the DOE’s Advanced Research Projects Agency-Energy, could contribute to a more advanced and reliable electric grid and help lower utility bills.

    The switch would consist of a plasma-filled tube that turns current on and off in systems that convert the direct current coming from long-distance power lines to the alternating current that lights homes and businesses; such systems are used to reverse the process as well.

    To assist GE, PPPL used a pair of computer codes to model the properties of plasma under different magnetic configurations and gas pressures. GE also studied PPPL’s use of liquid lithium, which the laboratory employs to prevent damage to the divertor that exhausts heat in a fusion facility. The information could help GE develop a method for protecting the liquid-metal cathode—the negative terminal inside the tube—from damage from the ions carrying the current flowing through the plasma.

    Laser experiments mimic cosmic explosions

    Scientists bring plasma tsunamis into the lab

    Researchers are finding ways to understand some of the mysteries of space without leaving earth. Using high-intensity lasers at the University of Rochester’s OMEGA EP Facility focused on targets smaller than a pencil’s eraser, they conducted experiments to create colliding jets of plasma knotted by plasma filaments and self-generated magnetic fields.

    In two related experiments, researchers used powerful lasers to recreate a tiny laboratory version of what happens at the beginning of solar flares and stellar explosions, creating something like a gigantic plasma tsunami in space. Much of what happens in those situations is related to magnetic reconnection, which can accelerate particles to high energy and is the force driving solar flares towards earth.

    Laboratory experiment aims to identify how tsunamis of plasma called “shock waves” form in space

    By W. Fox, G. Fisksel (LLE), A. Bhattacharjee

    William Fox, a researcher at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory, and his colleague Gennady Fiksel, of the University of Rochester, got an unexpected result when they used lasers in the Laboratory to recreate a tiny version of a gigantic plasma tsunami called a “shock wave.” The shock wave is a thin area found at the boundary between a supernova and the colder material around it that has a turbulent magnetic field that sweeps up plasma into a steep tsunami-like wave of plasma.

    Fox and Fiksel used two very powerful lasers to zap two tiny pieces of plastic in a vacuum chamber to 10 million degrees and create two colliding plumes of extremely hot plasma. The researchers found something they had not anticipated that had not previously been seen in the laboratory: When the two plasmas merged they broke into clumps of long thin filaments due to a process called the “Weibel instability.” This instability could be causing the turbulent magnetic fields that form the shock waves in space. Their research could shed light on the origin of primordial magnetic fields that formed when galaxies were created and could help researchers understand how cosmic rays are accelerated to high energies.

    Magnetic reconnection in the laboratory

    By: G. Fiksel (LLE), W. Fox, A. Bhattacharjee

    Many plasmas in space already contain a strong magnetic field, so colliding plasmas there behave somewhat differently. Gennady Fiksel, of the University of Rochester, and William Fox continued their previous research by adding a magnetic field by pulsing current through very small wires. They then created the two colliding plumes of plasma as they did in an earlier experiment. When the two plasmas collided it compressed and stretched the magnetic field and a tremendous amount of energy accumulated in the field like a stretched rubber band. As the magnetic field lines pushed close together, the long lines broke apart and reformed like a single stretched rubber band, forming a slingshot that propels the plasma and releases the energy into the plasma, accelerating the plasma and heating it.

    The experiment showed that the reconnection process happens faster than theorists had previously predicted. This could help shed light on solar flares and coronal mass ejections, which also happen extremely quickly. Coronal mass ejections can trigger geomagnetic storms that can interfere with satellites and wreak havoc with cellphone service.

    The laser technique the scientists are using is new in the area of high energy density plasma and allows scientists to control the magnetic field to manipulate it in various ways.

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
Follow

Get every new post delivered to your Inbox.

Join 452 other followers

%d bloggers like this: