From PPPL: “PPPL wins DOE funding for entrepreneurship”

From PPPL

November 13, 2019
Jeanne Jackson DeVoe

1
Craig Arnold, a professor of Aerospace Engineering at Princeton University, and founder of TAG Optics Inc., discusses his experiences starting a business at the Jan. 23 Entrepreneurship Lunch and Learn in the MBG Auditorium. (Photo by Elle Starkman/PPPL Office of Communications)

The U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) will expand an entrepreneurship “lunch and learn” program pioneered at PPPL last year and appoint mentors to help and encourage potential entrepreneurs in the Laboratory through two U.S. Department of Energy (DOE) projects totaling $70,000 awarded to PPPL’s Technology Transfer Office.

PPPL will participate in three and receive funding for two of 12 projects through DOE’s Practices to Accelerate the Commercialization of Technologies (PACT) program developed by DOE’s Office of Technology Transition (OTT) to help promote the transition of inventions developed at the 17 national laboratories and plants to the marketplace.

“I’m thrilled that PPPL received these awards,” said Laurie Bagley, head of Technology Transfer. “We are delighted to have the funding to provide support and training to our entrepreneurs, as well as to provide mentorship and training in collaboration with other laboratories.

A goal of instilling entrepreneurship

Steve Cowley, laboratory director, said he is glad to see funding for programs that encourage PPPL inventors. He noted that the DOE set a goal of instilling a culture of entrepreneurship as a “notable” requirement for all national laboratory directors in fiscal years 2019 and 2020. “One of PPPL’s major goals is to develop useful new technologies of all kinds,” Cowley said. “Laurie has done a wonderful job in developing programs to encourage entrepreneurship and these awards are a reflection of that. I hope everyone on our staff will take advantage of these programs and learn how to bring out their inner inventors.”

PPPL received $40,000 from the DOE’s Office of Technology Transitions to continue and expand the Entrepreneurship Lunch and Learn program begun last year by Bagley, to offer information and support to current and future entrepreneurs at the Laboratory. The additional funds will allow PPPL to bring in a wider variety of experts on a range of topics affecting entrepreneurs, Bagley said. Topics could include how to identify ideal customers, developing marketing leads and plans, intellectual property’s role in a start-up, and entrepreneur success stories. The talks could also help improve the skill set of inventors presenting their technologies at events such as the Innovation Discovery Events, technology showcases or Energy I-Corps programs, Bagley said.

This award is aimed at encouraging entrepreneurship throughout PPPL’s staff, not just physicists and engineers. “The goal is to get people here thinking more entrepreneurially, so if they are working on a technology that can be patented or have an idea to start a business, they’ll have a deeper understanding to make those decisions,” Bagley said.

PPPL’s Office of Technology Transfer offered four such talks last year to audience members and ranged from advice from a Princeton University entrepreneur on the challenges of starting a business to services available to entrepreneurs through Princeton University and the DOE’s Office of Technology Transition’s Program.

Funding for research liaisons

The Laboratory will also participate in a $30,000 project through a new pilot initiative, the DOE Technology Transfer Research Liaison Program. The program was championed by Oak Ridge National Laboratory (ORNL) as a collaborative effort with 11 national laboratories, including PPPL. The idea is to strengthen the relationship between the lab’s tech transfer office and its researchers and engineers to identify inventors and encourage and advise them about how to develop technologies, some of which can eventually be brought to market. PPPL will select three liaisons, who will receive training along with liaisons at other laboratories. The liaisons will then serve as champions and mentors by offering help and encouragement on questions about invention disclosures, patents, and other technology transfer issues.

In addition to the awards, PPPL was named as one of 11 partners in another new DOE program, Diversity and Inclusion in InVentorship and EntrepReneurship Strategies and Engagement (DIVERSE), which is aimed at encouraging a more diverse pool of inventors and entrepreneurs.

See the full article here .


five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition


PPPL campus

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.http://www.energy.gov.

Princeton University campus

#a-goal-of-instilling-entrepreneurship, #applied-research-technology, #basic-research, #funding-for-research-liaisons, #physics, #pppl, #pppl-wins-doe-funding-for-entrepreneurship

From PPPL- “Today’s forecast: How to predict crucial plasma pressure in future fusion facilities”

From PPPL

September 20, 2019
John Greenwald

1
Physicist Michael Churchill. (Photo by Elle Starkman/Office of Communications)

A key requirement for future facilities that aim to capture and control on Earth the fusion energy that drives the sun and stars is accurate predictions of the pressure of the plasma — the hot, charged gas that fuels fusion reactions inside doughnut-shaped tokamaks that house the reactions. Central to these predictions is forecasting the pressure that the scrape-off layer, the thin strip of gas at the edge of the plasma, exerts on the divertor — the device that exhausts waste heat from fusion reactions.

Researchers at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have developed new insights into the physics governing the balance of pressure in the scrape-off layer. This balance must ensure that the pressure of the plasma throughout the tokamak is high enough to produce a largely self-heating fusion reaction. The balance must also limit the potentially damaging impact of heat and plasma particles that strike the divertor and other plasma-facing components of the tokamak.

“Previous simple assumptions about the balance of pressure in the scrape-off layer are incomplete,” said PPPL physicist Michael Churchill, lead author of a Nuclear Fusion paper that describes the new findings. “The codes that simulate the scrape-off layer have often thrown away important aspects of the physics, and the field is starting to recognize this.”

Fusion, the power that drives the sun and stars, is the fusing of light elements in the form of plasma — the hot, charged state of matter composed of free electrons and atomic nuclei — that generates massive amounts of energy. Scientists are seeking to replicate fusion on Earth for a virtually inexhaustible supply of power to generate electricity.

Key factors

Churchill and PPPL colleagues determined the key factors behind the pressure balance by running the state-of-the-art XGCa computer code on the Cori and Edison supercomputers at the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility.

NERSC at LBNL

NERSC Cray Cori II supercomputer, named after Gerty Cori, the first American woman to win a Nobel Prize in science

NERSC Hopper Cray XE6 supercomputer, named after Grace Hopper, One of the first programmers of the Harvard Mark I computer

NERSC Cray XC30 Edison supercomputer

NERSC GPFS for Life Sciences


The Genepool system is a cluster dedicated to the DOE Joint Genome Institute’s computing needs. Denovo is a smaller test system for Genepool that is primarily used by NERSC staff to test new system configurations and software.

NERSC PDSF computer cluster in 2003.

PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations.

Future:

Cray Shasta Perlmutter SC18 AMD Epyc Nvidia pre-exascale supeercomputer

NERSC is a DOE Office of Science User Facility.

The code treats plasma at a detailed kinetic — or particle motion— level rather than as a fluid.

Among key features found was the impact of the bulk drift of ions, an impact that previous codes have largely ignored. Such drifts “can play an integral role” the authors wrote, and “are very important to take into account.”

Also seen to be important in the momentum or pressure balance were the kinetic particle effects due to ions having different temperatures depending on their direction. Since the temperature of ions is hard to measure in the scrape-off layer, the paper says, “increased diagnostic efforts should be made to accurately measure the ion temperature and flows and thus enable a better understanding of the role of ions in the SOL.”

The new findings could improve understanding of the scrape-off layer pressure at the divertor, Churchill said, and could lead to accurate forecasts for the international ITER experiment under construction in France and other next-generation tokamaks.

ITER Tokamak in Saint-Paul-lès-Durance, which is in southern France

Support for this work comes from the DOE Office of Science under the SciDAC Center for High Fidelity Boundary Plasma Simulation (HBPS). The research used resources of the National Energy Research Scientific Computing Center (NERSC). Coauthors of the paper were PPPL physicists C.S Chang, Seung-Ho Ku, Robert Hager, Rajesh Maingi, Daren Stotler and Hong Qin.

See the full article here .


five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition


PPPL campus

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.http://www.energy.gov.

Princeton University campus

#how-to-predict-crucial-plasma-pressure-in-future-fusion-facilities, #accurate-predictions-of-the-pressure-of-the-plasma, #applied-research-technology, #fusion-technology, #physics, #pppl

From PPPL: “New national facility will explore low-temperature plasma, a dynamic source of innovation for modern technologies”

From PPPL

September 5, 2019
John Greenwald

1
Princeton collaborative research team from left: Mikhail Shneider; Igor Kaganovich; Yevgeny Raitses; Sophia Gershman; Nirbhav Chopra, Princeton plasma physics graduate student who will use the new facility; Shurik Yatom; Arthur Dogariu. (Photo by Elle Starkman/Office of Communications)

Low-temperature plasma, a rapidly expanding source of innovation in fields ranging from electronics to health care to space exploration, is a highly complex state of matter. So complex that the Princeton Plasma Physics Laboratory (PPPL) has teamed with Princeton University to become home to a collaborative facility open to researchers from across the country to advance the understanding and control of this dynamic physical state.

Extensive resources

The new facility, to launch this October with U.S. Department of Energy (DOE) funding of $1.2 million a year for five years, opens the extensive diagnostic and computational resources at PPPL and Princeton to the academic, scientific and industrial communities. More than 40 researchers are estimated to be interested in topics that the facility will explore, said PPPL physicist Yevgeny Raitses, principal investigator of the new unit, the Princeton Collaborative Research Facility on Low Temperature Plasma.

Raitses heads the PPPL Laboratory for Plasma Nanosynthesis, which pioneers research on low-temperature plasma to improve the production of nanoparticles — substances millions of times thinner than a human hair found in everything from swimwear to pharmaceuticals. All state-of-the-art instruments housed in the plasma nanosynthesis laboratory will become available to collaborators in the new facility.

Raitses and physicist Igor Kaganovich, deputy head of the PPPL Theory Department, have long extended the outreach of low-temperature plasma research. Over the past 10 years they have collaborated with companies on topics ranging from the fabrication of microchips to the production of medical treatments to the development of a power switch to modernize the electric grid.

“World-class program”

Such companies could now make use of the new facility. “I am delighted with this award,” PPPL Director Steve Cowley said of the new collaborative unit. “Through the leadership of Yevgeny and Igor and collaborations with Princeton University we have developed a world-class program in low temperature plasma science — this will take us to another level.”

Low-temperature plasma contrasts with the superhot plasma that PPPL investigates that fuels the fusion energy that powers the sun and stars. Fusion plasmas consist chiefly of free-floating electrons and atomic nuclei, or ions, while low-temperature plasmas, which are up to 10,000 times cooler, include a large complement of neutral and partially ionized atoms mixed in with these particles.

The mixture interacts with solids and liquids to produce applications in a wide range of fields. Among the key topics the facility will explore are interactions with liquids that can affect chemical processes and improve the production of environmental and health care systems, to cite two examples.

New explorations

Also to be explored is the interface between plasma and solid-state physics. The process could lead to low-cost and high-volume production of photovoltaic cells for turning sunlight into electricity, among other developments affecting solid-state matter.

Hosting such research comes naturally to PPPL, the only national laboratory dedicated to the study of fusion energy and plasma science. “It’s important for the nation’s plasma physics lab to make a major contribution to understanding the physics of low-temperature plasmas,” said Jon Menard, deputy director for research at PPPL. “This facility will open all the tools in the laboratory’s low-temperature area for wider use.”

Scientists at PPPL and Princeton will provide guidance to collaborators who come to the facility from companies, universities and laboratories throughout the country. Among physicists joining Raitses and Kaganovitch on the PPPL team will be Sophia Gershman, an expert in the interaction of plasma and liquids, and Shurik Yatom, who has developed methods for characterizing the synthesis of nanoparticles in plasma in situ, or while the process is taking place. Additional PPPL physicists will conduct research and give guidance to researchers using of the facility.

Princeton laboratories and centers

Heading the Princeton University team will be physicists Mikhail Shneider, an expert in plasma physics, fluid dynamics and non-linear optics, who will serve as co-principal investigator. Arthur Dogariu, who pioneered several advanced optical diagnostic techniques, will lead the collaborative center’s experimental efforts at Princeton. University laboratories and centers, including the Princeton Institute for the Science and Technology of Materials (PRISM), will provide access to collaborators, with faculty members and graduate students serving as users and partners in the new facility.

The total venture, supported by the DOE’s Office of Science, will be part of the Plasma Science and Technology Department at PPPL that physicist Philip Efthimion heads. “We’ll be offering our diagnostic and computer modeling tools to the research community and the private sector,” Efthimion said. “This will provide new opportunities to collaborate between the community and the private sector and to expand our research on low-temperature plasmas.”

See the full article here .


five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition


PPPL campus

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.http://www.energy.gov.

Princeton University campus

#new-national-facility-will-explore-low-temperature-plasma-a-dynamic-source-of-innovation-for-modern-technologies, #also-to-be-explored-is-the-interface-between-plasma-and-solid-state-physics, #low-temperature-plasma-contrasts-with-the-superhot-plasma-that-pppl-investigates-that-fuels-the-fusion-energy-that-powers-the-sun-and-stars, #pppl, #scientists-at-pppl-and-princeton-will-provide-guidance-to-collaborators-who-come-to-the-facility-from-companies-universities-and-laboratories-throughout-the-country, #the-new-facility-will-launch-this-october-with-u-s-department-of-energy-doe-funding-of-1-2-million-a-year-for-five-years, #the-princeton-plasma-physics-laboratory-pppl-has-teamed-with-princeton-university-to-become-home-to-a-collaborative-facility-open-to-researchers-from-across-the-country, #the-total-venture-supported-by-the-does-office-of-science-will-be-part-of-the-plasma-science-and-technology-department-at-pppl

From PPPL: “Artificial intelligence accelerates efforts to develop clean, virtually limitless fusion energy”

From PPPL

April 17, 2019 [Just found this in social media]
John Greenwald

1
Depiction of fusion research on a doughnut-shaped tokamak enhanced by artificial intelligence. (Depiction by Eliot Feibush/PPPL and Julian Kates-Harbeck/Harvard University)

Artificial intelligence (AI), a branch of computer science that is transforming scientific inquiry and industry, could now speed the development of safe, clean and virtually limitless fusion energy for generating electricity. A major step in this direction is under way at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and Princeton University, where a team of scientists working with a Harvard graduate student is for the first time applying deep learning — a powerful new version of the machine learning form of AI — to forecast sudden disruptions that can halt fusion reactions and damage the doughnut-shaped tokamaks that house the reactions.

Promising new chapter in fusion research

“This research opens a promising new chapter in the effort to bring unlimited energy to Earth,” Steve Cowley, director of PPPL, said of the findings, which are reported in the current issue of Nature magazine. “Artificial intelligence is exploding across the sciences and now it’s beginning to contribute to the worldwide quest for fusion power.”

Fusion, which drives the sun and stars, is the fusing of light elements in the form of plasma — the hot, charged state of matter composed of free electrons and atomic nuclei — that generates energy. Scientists are seeking to replicate fusion on Earth for an abundant supply of power for the production of electricity.

Crucial to demonstrating the ability of deep learning to forecast disruptions — the sudden loss of confinement of plasma particles and energy — has been access to huge databases provided by two major fusion facilities: the DIII-D National Fusion Facility that General Atomics operates for the DOE in California, the largest facility in the United States, and the Joint European Torus (JET) in the United Kingdom, the largest facility in the world, which is managed by EUROfusion, the European Consortium for the Development of Fusion Energy. Support from scientists at JET and DIII-D has been essential for this work.

DOE DIII-D Tokamak

Joint European Torus, at the Culham Centre for Fusion Energy in the United Kingdom

The vast databases have enabled reliable predictions of disruptions on tokamaks other than those on which the system was trained — in this case from the smaller DIII-D to the larger JET. The achievement bodes well for the prediction of disruptions on ITER, a far larger and more powerful tokamak that will have to apply capabilities learned on today’s fusion facilities.


ITER Tokamak in Saint-Paul-lès-Durance, which is in southern France

The deep learning code, called the Fusion Recurrent Neural Network (FRNN), also opens possible pathways for controlling as well as predicting disruptions.

Most intriguing area of scientific growth

“Artificial intelligence is the most intriguing area of scientific growth right now, and to marry it to fusion science is very exciting,” said Bill Tang, a principal research physicist at PPPL, coauthor of the paper and lecturer with the rank and title of professor in the Princeton University Department of Astrophysical Sciences who supervises the AI project. “We’ve accelerated the ability to predict with high accuracy the most dangerous challenge to clean fusion energy.”

Unlike traditional software, which carries out prescribed instructions, deep learning learns from its mistakes. Accomplishing this seeming magic are neural networks, layers of interconnected nodes — mathematical algorithms — that are “parameterized,” or weighted by the program to shape the desired output. For any given input the nodes seek to produce a specified output, such as correct identification of a face or accurate forecasts of a disruption. Training kicks in when a node fails to achieve this task: the weights automatically adjust themselves for fresh data until the correct output is obtained.

A key feature of deep learning is its ability to capture high-dimensional rather than one-dimensional data. For example, while non-deep learning software might consider the temperature of a plasma at a single point in time, the FRNN considers profiles of the temperature developing in time and space. “The ability of deep learning methods to learn from such complex data make them an ideal candidate for the task of disruption prediction,” said collaborator Julian Kates-Harbeck, a physics graduate student at Harvard University and a DOE-Office of Science Computational Science Graduate Fellow who was lead author of the Nature paper and chief architect of the code.

Training and running neural networks relies on graphics processing units (GPUs), computer chips first designed to render 3D images. Such chips are ideally suited for running deep learning applications and are widely used by companies to produce AI capabilities such as understanding spoken language and observing road conditions by self-driving cars.

Kates-Harbeck trained the FRNN code on more than two terabytes (1012) of data collected from JET and DIII-D. After running the software on Princeton University’s Tiger cluster of modern GPUs, the team placed it on Titan, a supercomputer at the Oak Ridge Leadership Computing Facility, a DOE Office of Science User Facility, and other high-performance machines.

Tiger Dell Linux supercomputer at Princeton University

ORNL Cray XK7 Titan Supercomputer, once the fastest in the world, now No.9 on the TOP500

A demanding task

Distributing the network across many computers was a demanding task. “Training deep neural networks is a computationally intensive problem that requires the engagement of high-performance computing clusters,” said Alexey Svyatkovskiy, a coauthor of the Nature paper who helped convert the algorithms into a production code and now is at Microsoft. “We put a copy of our entire neural network across many processors to achieve highly efficient parallel processing,” he said.

The software further demonstrated its ability to predict true disruptions within the 30-millisecond time frame that ITER will require, while reducing the number of false alarms. The code now is closing in on the ITER requirement of 95 percent correct predictions with fewer than 3 percent false alarms. While the researchers say that only live experimental operation can demonstrate the merits of any predictive method, their paper notes that the large archival databases used in the predictions, “cover a wide range of operational scenarios and thus provide significant evidence as to the relative strengths of the methods considered in this paper.”

From prediction to control

The next step will be to move from prediction to the control of disruptions. “Rather than predicting disruptions at the last moment and then mitigating them, we would ideally use future deep learning models to gently steer the plasma away from regions of instability with the goal of avoiding most disruptions in the first place,” Kates-Harbeck said. Highlighting this next step is Michael Zarnstorff, who recently moved from deputy director for research at PPPL to chief science officer for the laboratory. “Control will be essential for post-ITER tokamaks – in which disruption avoidance will be an essential requirement,” Zarnstorff noted.

Progressing from AI-enabled accurate predictions to realistic plasma control will require more than one discipline. “We will combine deep learning with basic, first-principle physics on high-performance computers to zero in on realistic control mechanisms in burning plasmas,” said Tang. “By control, one means knowing which ‘knobs to turn’ on a tokamak to change conditions to prevent disruptions. That’s in our sights and it’s where we are heading.”

Support for this work comes from the Department of Energy Computational Science Graduate Fellowship Program of the DOE Office of Science and National Nuclear Security Administration; from Princeton University’s Institute for Computational Science and Engineering (PICsiE); and from Laboratory Directed Research and Development funds that PPPL provides. The authors wish to acknowledge assistance with high-performance supercomputing from Bill Wichser and Curt Hillegas at PICSciE; Jack Wells at the Oak Ridge Leadership Computing Facility; Satoshi Matsuoka and Rio Yokata at the Tokyo Institute of Technology; and Tom Gibbs at NVIDIA Corp.

See the full article here .


five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition


PPPL campus

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

#artificial-intelligence-ai, #deep-learning, #fusion-technology, #pppl

From PPPL: “Novel experiment validates a widely speculated and important mechanism during the formation of stars and planets”


From PPPL

February 5, 2019
John Greenwald

1
Water-filled version of MRI [magnetorotational instability] experiment showing transparent outer cylinder and blackened inner cylinder. Red lasers enter at bottom to measure the local speed of the water. (Photo courtesy of Eric Edlund and Elle Starkman)

How have stars and planets developed from the clouds of dust and gas that once filled the cosmos? A novel experiment at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) has demonstrated the validity of a widespread theory known as “magnetorotational instability,” or MRI, that seeks to explain the formation of heavenly bodies.

The theory holds that MRI allows accretion disks, clouds of dust, gas, and plasma that swirl around growing stars and planets as well as black holes, to collapse into them. According to the theory, this collapse happens because turbulent swirling plasma, technically known as “Keplerian flows,” gradually grows unstable within a disk. The instability causes angular momentum — the process that keeps orbiting planets from being drawn into the sun — to decrease in inner sections of the disk, which then fall into celestial bodies.

Unlike orbiting planets, the matter in dense and crowded accretion disks may experience forces such as friction that cause the disks to lose angular momentum and be drawn into the objects they swirl around. However, such forces cannot fully explain how quickly matter must fall into larger objects for planets and stars to form on a reasonable timescale.

MRI experiment

At PPPL, physicists have simulated the hypothesized broader process in the laboratory’s MRI experiment. The unique device consists of two concentric cylinders that rotate at different speeds. In this experiment, researchers filled the cylinders with water and attached a water-filled plastic ball tethered by a spring to a post in the center of the device; the stretching and bending spring mimicked the magnetic forces in the plasma in accretion disks. Researchers then rotated the cylinders and videoed the behavior of the ball as seen from the top down.

The findings, reported in Communications Physics, compared the motions of the spring-tethered ball when rotating at different speeds. “With no stretching, nothing happens to the angular momentum,” said Hantao Ji, a professor of astrophysical sciences at Princeton University and principal researcher on the MRI and a coauthor of the paper. “Nothing also happens if the spring is too strong.”

However, direct measurement of the results found that when the spring-tethering was weak — analogous to the condition of the magnetic fields in accretion disks —behavior of the angular momentum of the ball was consistent with MRI predictions of developments in a real accretion disk. The findings showed that the weakly tethered rotating ball gained angular momentum and shifted outward during the experiment. Since the angular momentum of a rotating body must be conserved, any gains in momentum must be matched by a loss of momentum in the inner section, allowing gravity to draw the disk into the object it has been orbiting.

Contributing to research for this paper was lead author Derek Hung, a former Princeton graduate student, together with physicists Erik Gilson and Kyle Caspary of PPPL and astrophysicist Eric Blackman of the Department of Physics and Astronomy and the Laboratory for Laser Energetics at the University of Rochester, who brought up the idea. Support for this work comes from NASA, the National Science Foundation, the DOE Office of Science, the Simons Foundation, the Institute for Advanced Study, and the Kavli Institute for Theoretical Physics.

See the full article here .


five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition


PPPL campus

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

#astronomy, #astrophysics, #basic-research, #cosmology, #mri-magnetorotational-instability, #pppl

From PPPL: “Experiments at PPPL show remarkable agreement with satellite sightings”


From PPPL

December 7, 2018
John Greenwald

1
Members of the MRX team with the device in the background. From left, Masaaki Yamada, Jongsoo Yoo, Jonathan Jara-Almonte, Will Fox, and Hantao Ji.
(Photo by Elle Starkman/PPPL Office of Communications)

1
Illustration of the MMS spacecraft in orbit in Earth’s magnetic field. NASA

As on Earth, so in space. A four-satellite mission that is studying magnetic reconnection — the breaking apart and explosive reconnection of the magnetic field lines in plasma that occurs throughout the universe — has found key aspects of the process in space to be strikingly similar to those found in experiments at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL). The similarities show how the studies complement each other: The laboratory captures important global features of reconnection and the spacecraft documents local key properties as they occur.

NASA Magnetic reconnection, Credit: M. Aschwanden et al. (LMSAL), TRACE, NASA

The observations made by the Magnetospheric Multiscale Satellite (MMS) mission, which NASA launched in 2015 to study reconnection in the magnetic field that surrounds the Earth, correspond quite well with past and present laboratory findings of the Magnetic Reconnection Experiment (MRX) at PPPL. Previous MRX research uncovered the process by which rapid reconnection occurs and identified the amount of magnetic energy that is converted to particle energy during the process, which gives rise to northern lights, solar flares and geomagnetic storms that can disrupt cell phone service, black out power grids and damage orbiting satellites.

Guidelines for MMS measurements

The previous MRX findings served as guidelines for measurements taken by the MMS mission, which seeks to understand the region in which the reconnection of field lines in plasma — the state of matter composed of free electrons and atomic nuclei, or ions — takes place. The latest PPPL experiments extend the findings to new areas of agreement. “Despite huge differences in the size of the reconnection layers in the MRX and in space, remarkably similar characteristics are observed in both,” said Masaaki Yamada, principal investigator on the MRX, and lead author of the recent paper reporting the results in the December 6 edition of Nature Communications .

The past laboratory research examined “symmetric” reconnection, in which the density of the plasmas on each side of the reconnection regions are roughly the same. The new paper looks at reconnection in the magnetopause — the outer region of the magnetosphere — and in the MRX that is “asymmetric,” meaning that the plasma on one side of the region is at least 10 times denser than on the other. The MMS mission has focused its initial research on the asymmetric aspect of reconnection, since the plasma in the solar wind — the charged particles flowing from the sun — is vastly denser than the plasma in the magnetosphere.

In the new paper, researchers examine what is called the “two-fluid” physics of reconnection that describes each behavior of ions and electrons differently during the process. Such physics dominates magnetic reconnection in both MRX and magnetospheric plasma systems, allowing for an unprecedented level of cross-examination between laboratory measurements and space observations.

Key findings

Following are key findings of the two-fluid, asymmetric research on MRX that is shown to be in striking agreement with measurements of electron and ion behavior by the space satellites and the conversion of magnetic energy to particle energy. Computer simulations aided these findings:

• Electrons. The experiments demonstrated that electron current flows perpendicular, and not parallel as once thought, to the magnetic field. This flow is key to the conversion of magnetic energy in electrons that occurs in a narrow boundary layer called the “electron diffusion region” where rapid reconnection takes place. The finding is consistent with the recent MMS space measurements and new in the laboratory for asymmetric reconnection.

• Ions. The ion current also flows perpendicular to the magnetic field as in the electron case, and likewise is key to the conversion of ion magnetic energy to particle energy. For ions, this conversion occurs in the wider “ion diffusion region” between converging plasmas and is a similarly recent finding about asymmetric reconnection in laboratory plasmas.

The MRX experiments further studied different aspects of conversion in the symmetric and asymmetric cases. In symmetric reconnection, 50 percent of magnetic energy was previously found to be converted to ions and electrons, with one-third of the conversion affecting the electrons and two-thirds accelerating the ions. The total conversion rate remains roughly the same in the asymmetric case, as does the ratio of energy conversion for ions and electrons.

PPPL researchers contributing to this study were Jongsoo Yoo, Will Fox, Jonathan Jara-Almote and Hantao Ji. Also contributing were physicists at the NASA Goddard Space Flight Center, Los Alamos National Laboratory, the Southwest Research Institute, and the universities of New Hampshire and Bergen in Bergen, Norway. Computer simulations were conducted at Los Alamos National Laboratory. Support for this work comes from DOE’s Office of Science, NASA, and the National Science Foundation.

See the full article here .


five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition


PPPL campus

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

#magnetic-reconnection, #magnetospheric-multiscale-satellite-mms-mission-launched-in-2015, #physics, #pppl, #princeton-magnetic-reconnection-experiment-mrx-at-pppl

From PPPL: “Turbulence in space might solve outstanding astrophysical mystery”


From PPPL

November 5, 2018
Raphael Rosen

1
PPPL graduate student Denis St-Onge. (Photo by Elle Starkman)

Contrary to what many people believe, outer space is not empty. In addition to an electrically charged soup of ions and electrons known as plasma, space is permeated by magnetic fields with a wide range of strengths. Astrophysicists have long wondered how those fields are produced, sustained, and magnified. Now, scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have shown that plasma turbulence might be responsible, providing a possible answer to what has been called one of the most important unsolved problems in plasma astrophysics.

The researchers used powerful computers at the Princeton Institute for Computational Science and Engineering (PICSciE) and the National Energy Research Scientific Computing Center (NERSC) at the DOE’s Lawrence Berkeley National Laboratory to simulate how the turbulence could intensify magnetic fields through what is known as the dynamo effect, in which the magnetic fields become stronger as the magnetic field lines twist and turn.

Tiger Dell Linux supercomputer at Princeton University

NERSC

NERSC Cray Cori II supercomputer at NERSC at LBNL, named after Gerty Cori, the first American woman to win a Nobel Prize in science


LBL NERSC Cray XC30 Edison supercomputer


The Genepool system is a cluster dedicated to the DOE Joint Genome Institute’s computing needs. Denovo is a smaller test system for Genepool that is primarily used by NERSC staff to test new system configurations and software.

NERSC PDSF


PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations.

“This work constitutes an important step toward answering for the first time the question of whether turbulence can amplify magnetic fields to dynamical strengths in a hot, dilute plasma, such as that residing within clusters of galaxies,” said Matthew Kunz, an astrophysics professor at Princeton University and an author of the paper, which was published in The Astrophysical Journal Letters.

Past research has focused on dynamos as they might occur in so-called collisional plasmas, in which particles collectively behave as a fluid. But intergalactic plasmas are collisionless, so past experiments are not necessarily relevant. This new research is meant to address that gap. “We wanted to see how the dynamo would behave in the collisionless regime,” said Denis St-Onge, graduate student in the Princeton Program in Plasma Physics at PPPL and lead author of the paper.

St-Onge and Kunz focused on the ways in which the velocities and magnetic fields of individual particles within collisionless plasma are directly linked. This linkage — if one quantity increases or decreases, the other must, too — would seem to rule out the existence of a dynamo. “If this were the whole story, it would be disastrous for the dynamo,” said St-Onge. “To match what we observe in space, the dynamo would have to increase the strength of the seed magnetic field by at least a factor of one trillion, but the energy of the particles would also have to increase, and there’s just not enough available energy in the dynamo for that to happen.”

To produce the strength of magnetic fields observed in space, the tie that binds particle energy to magnetism must be severed. This is just what St-Onge and Kunz observed in the computer simulations: that types of plasma turbulence known as mirror and firehose instabilities caused the plasma particles to scatter, and scattering broke the link between particle energy and magnetism and allowed the amplitudes of the magnetic fields to grow closer to what is observed in nature.

Future research, St-Onge notes, will focus on why this turbulent scattering occurs. “In addition, we would like to investigate the specifics of particle scattering,” St-Onge said. “How exactly do the instabilities cause the particles to scatter, how often does the scattering occur, and can the scattering lead to sudden, dramatic growth of a magnetic field? The last idea is a notion proposed by PPPL Director Steven Cowley years ago. We would like to investigate whether this is true.”

See the full article here .


five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition


PPPL campus

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

#astronomy, #astrophysics, #basic-research, #cosmology, #plasma-turbulence, #pppl, #space-is-permeated-by-magnetic-fields-with-a-wide-range-of-strengths, #turbulence-in-space-might-solve-outstanding-astrophysical-mystery