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  • richardmitnick 8:36 pm on December 8, 2014 Permalink | Reply
    Tags: , , , , Princeton Plasma Physics Laboratory,   

    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.

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

     
  • richardmitnick 9:35 pm on November 17, 2014 Permalink | Reply
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    From PPPL: “PPPL, Princeton launch hunt for Big Bang particles offering clues to the origin of the universe” 


    PPPL

    November 17, 2014
    John Greenwald

    Billions upon billions of neutrinos speed harmlessly through everyone’s body every moment of the day, according to cosmologists. The bulk of these subatomic particles are believed to come straight from the Big Bang, rather than from the sun or other sources. Experimental confirmation of this belief could yield seminal insights into the early universe and the physics of neutrinos. But how do you interrogate something so elusive that it could zip through a barrier of iron a light-year thick as if it were empty space?

    At the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL), researchers led by Princeton University physicist Chris Tully are set to hunt for these nearly massless Big Bang relics by exploiting a curious fact: Neutrinos can be captured by tritium, a radioactive isotope of hydrogen, and provide a tiny boost of energy to the electrons — or beta particles — that are emitted in tritium decay.

    Tully has created a prototype lab at PPPL to detect Big Bang neutrinos by measuring the extra energy they impart to the electrons — and to achieve this with greater precision than has ever been done before. Spotting these neutrinos is akin to “detecting a faint heartbeat in a sports arena filled to the brim” said Charles Gentile, who heads engineering for the project, which Tully has dubbed PTOLEMY for “Princeton Tritium Observatory for Light, Early Universe Massive Neutrino Yield.” Ptolemy was an ancient Greek astronomer who lived in Egypt during the first century.

    Darkest, coldest conditions achievable

    The task calls for measuring the energy of an electron with a precision comparable to detecting the mass of a neutrino, which until recently was thought to have no mass at all. Such measurements require the darkest, coldest conditions achievable in a laboratory and the use of quantum electronics — a discipline that deals with the effect of quantum mechanics on the behavior of electrons in matter — to detect the minute extra energy that a Big Bang neutrino would impart. Quantum mechanics describes the motion and direction of subatomic particles.

    Why is the energy that a Big Bang neutrino provides so extraordinarily small? What’s unique about these relics is that their wavelength has been stretched and cooled as the space-time we live in has expanded over approximately 13.7 billion years. This expansion has cooled a tremendous number of neutrinos to temperatures that are billions of times colder, and therefore less energetic, than those of neutrinos originating from the sun. When tritium captures these cold neutrinos, they create a narrow peak in energy that is just above the maximum energy of an electron from tritium decay.

    The difficulty in identifying a Big Bang relic doesn’t end there. Since neutrinos can take different forms, the height of the peak could be higher or lower by a factor of two, depending on whether the neutrino is like normal matter with a corresponding particle of antimatter — an antineutrino — or whether the neutrino is different and is in fact its own antiparticle. The extra height might not appear at all if neutrinos decay over billions of years into yet unknown, lighter particles.

    Cutting-edge technology

    Tully aims to show that the prototype for PTOLEMY, which is housed in a basement site at PPPL, can indeed achieve the precision needed to detect Big Bang neutrinos. The cutting-edge technology could then become the basis for a major experiment at PPPL to test long-held assumptions about the density of Big Bang neutrinos throughout the universe.

    b
    Chris Tully, front left, and Charles Gentile, front right, with participants in the PTOLEMY project under construction. Back row from left: Irving Zatz, Robert Woolley, Lloyd Ciebiera, Junast Suerfu, Doug Westover, Philip G. Efthimion, William Sands, Jim Taylor. (Photo by Elle Starkman / PPPL Office of Communications)

    Confirming the assumptions could validate the standard model of the origin of the universe, Tully says, while refuting them could overturn the model and prompt new ideas about the Big Bang and its aftermath. Finding the neutrinos could also show if they could be a source of the invisible dark matter that scientists say makes up 20 percent of the total mass of the universe.

    Such discoveries could be epochal. Could the project “make long-term contributions to the understanding of the universe?” Tully asks in presentations about PTOLEMY. “Absolutely!” he says. “We believe that we live in a sea of 14 billion-year-old neutrinos all around us. But is it true?”

    The prototype at PPPL may hold the key to finding out. The device consists of a pair of superconducting magnets connected to opposite ends of a five-foot cylindrical vacuum chamber. A source containing a tiny bit of tritium sits inside one end of the chamber, with a calorimeter that Argonne National Laboratory is providing to measure electron energy set at the other end. The experiment will bind electrons from the tritium decay to magnetic field lines and pass them through filters in the vacuum chamber that will remove all but the highest-energy electrons, which the calorimeter will then measure.

    Preventing “noise”

    Great care will be taken to keep random thermal “noise” from disrupting the finely tuned equipment at each end of the experiment. Researchers will deposit the tritium on the nanomaterial graphene — a layer of carbon just one atom thick — to ensure that the electrons come off cleanly into the vacuum.

    The calorimeter at the other end of the chamber will be connected to a dilution refrigerator set at between 70 and 100 millikelvins, a temperature 20 times colder than deep space and less than one-tenth of a degree above absolute zero. This deep-freeze will keep the calorimeter poised between a superconducting state — one in which electrons can flow with virtually no resistance — and a non-superconducting state with resistance to the flow of electrons. The delicate balance between these two states, combined with extremely low noise conditions achievable only with quantum electronics, will provide the sensitivity needed to precisely measure the energy of an electron that impinges upon the calorimeter. The setup will produce “the most precise electron-energy measurements ever made using calorimeter techniques,” Tully said.

    This experiment is “a perfect match for the competencies and capabilities that exist at PPPL,” said Adam Cohen, deputy director for operations at PPPL and supervisor of the PTOLEMY project. Such qualities include know-how in handling tritium, a laboratory for synthesizing nanomaterial, decades of experience operating magnets and vacuum vessels, and space for an expanded experiment. “Chris and I talked about collaboration between PPPL and the University about three years ago,” Cohen recalled. “Every time we pursue an activity with the campus it strengthens the bridge that exists between us.”

    Looking ahead, Cohen sees PTOLEMY attracting new students, researchers and visitors, along with experts in high-energy physics, to PPPL. This could produce cross-fertilization with the Laboratory’s core mission of advancing fusion and plasma science, he said.

    For Tully, PTOLEMY could become the gateway to many avenues of research. “When one opens a new frontier of exploration,” he noted, “there is no telling what will be found and learned.”

    ct
    Chris Tully making adjustments (Photo by Elle Starkman / PPPL Office of Communications)

    See the full article here.

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  • richardmitnick 2:29 pm on November 11, 2014 Permalink | Reply
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    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.

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  • richardmitnick 7:10 am on November 11, 2014 Permalink | Reply
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    From PPPL: “Hole in one: Technicians smoothly install the center stack in the NSTX-U vacuum vessel” 


    PPPL

    November 10, 2014
    John Greenwald

    With near-surgical precision, PPPL technicians hoisted the 29,000-pound center stack for the National Spherical Torus Experiment-Upgrade (NSTX-U) over a 20-foot wall and lowered it into the vacuum vessel of the fusion facility. The smooth operation on Oct. 24 capped more than two years of construction of the center stack, which houses the bundle of magnetic coils that form the heart of the $94 million upgrade.

    lift
    Closeup of the center stack being lowered into position by an overhead crane. (Photo by Elle Starkman/PPPL Office of Communications)

    “This was really a watershed moment,” said Mike Williams, the head of engineering and infrastructure at PPPL and associate director of the Laboratory. “The critical path [or key sequence of steps for the upgrade] was fabrication of the magnets, and that has now been done.”

    The lift team conducted the final steps largely in silence, attaching the bundled coils in their casing to an overhead crane and guiding the 21 foot-long center stack into place. The clearances were tiny: The bottom of the casing passed just inches over the shielding wall and the top of the vacuum vessel. Inserting the center stack into the vessel was like threading a needle, since the clearance at the opening was only about an inch. Guidance came chiefly from hand signals, with some radio communication at the end.

    more

    Key features

    The installation merged three key features of the upgrade that had been developed separately. These included the casing, the bundled coils and the work to ready the vacuum vessel for the center stack. Slipping the casing over the bundle was a highly precise task, with the space between them less than an inch. “The key word is ‘fit-up,’” said Ron Strykowsky, who heads the upgrade project. “We had a robust-enough design to handle all the very fine tolerances.”

    Installation of the center stack completed a key portion of the upgrade and opened another chapter. “For me, the burden is off our shoulders,” said Jim Chrzanowski, who led the coil project and retired on Oct. 31 after 39 years at PPPL. “We’ve delivered the center stack and are happy,” added Steve Raftopoulos, who worked alongside Chrzanowski and succeeds him as head of coil building. “This is my baby now,” said Raftopoulos, noting that he will be called on to resolve any problems that occur once the center stack is in operation.

    Praise for technicians

    The two leaders praised the many technicians who made the center stack possible. They ranged from a core of roughly a dozen workers who had been with the project from the beginning to technicians throughout the Laboratory who were called on to pitch in. “We drafted everyone,” Chrzanowski said.

    Their tasks included sanding, welding and applying insulation tape to each of the 36 copper conductors that went into the center stack, and sealing them all together through multiple applications of vacuum pressure impregnation — a potentially volatile process. Next came fabrication and winding of the ohmic heating coil that wraps around the conductors to put current into the hot, charged plasma that fuels fusion reactions.

    “Everyone who worked on this feels a lot of pride and ownership,” Raftopoulos said. “Steve and I were the conductors, but the technicians were the orchestra,” Chrzanowski said. “We’ve got to give credit to the guys who actually build the machines. They take our problems and make them go away.”

    Completion of the upgrade now rests with technicians working under engineer Erik Perry. Their jobs include connecting the center stack to the facility’s outer coils to complete a donut-shape magnetic field that will be used to confine the plasma. The work calls for installation of layers of custom-made electrical equipment plus hoses for water to cool the coils, all of which must fit around diagnostic and other equipment. Also ahead lies the task of connecting a second neutral beam injector for heating the plasma to the vacuum vessel. “It’s like a big puzzle,” said Perry. “Everything must fit together, and that’s what we excel at.”

    See the full article here.

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  • richardmitnick 6:52 pm on October 28, 2014 Permalink | Reply
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    From PPPL: “Bob Ellis designs a PPPL first: A 3D printed mirror for microwave launchers” 


    PPPL

    October 28, 2014
    John Greenwald

    When scientists at the Korea Supercomputing Tokamak Advanced Research (KSTAR) facility needed a crucial new component, they turned to PPPL engineer Bob Ellis. His task: Design a water-cooled fixed mirror that can withstand high heat loads for up to 300 seconds while directing microwaves beamed from launchers to heat the plasma that fuels fusion reactions.

    be
    Bob Ellis with a 3D-printed plastic prototype for a non-mirror part of the launcher. (Photo by Elle Starkman/PPPL Office of Communications)

    kstar
    KSTAR Tokamak

    Ellis, who had designed mirrors without coolant for shorter experiments, decided to try out a novel manufacturing process called 3D printing that produces components as unified wholes with minimal need for further processing. 3D printing would enable the mirror to be built for less cost than a non-water-cooled mirror produced by conventional manufacturing, Ellis said, “and that was a very nice thing to find out about.”

    The project marked a first for PPPL, which had previously used 3D printers to build plastic models but had not employed the process for creating metal parts. “Metal came into 3D printing about five years ago and was sort of exotic then,” said Phil Heitzenroeder, who heads the Mechanical Engineering Division at PPPL. “Now 3D is beginning to drift down into real-world metal products.”

    Ellis created a CAD-CAM model of the shoebox-size mirror system and delivered it to Imperial Machine & Tool Co. to produce the stainless steel and copper component through metal 3D printing. The process puts down hair-thin layers of stainless steel powder and fuses the powder in each layer with lasers. The parts are thus built from the bottom up layer by layer — another name for 3D printing is “additive manufacturing” — and follow every twist and turn of the CAD-CAM design.

    The stainless steel granules have the consistency of talcum powder before they are fused, said Christian M. Joest, president of the 70-year-old Columbia, N.J., machining and fabricating company. The 3D process took about 20 hours to complete, Joest said.

    The process proved ideal for the water-cooled mirror, which PPPL shipped to KSTAR in early October. The part consists of a thin sheet of polished copper mounted atop a stainless steel base, with serpentine channels for water winding through the base’s center. Conventional construction could have required the base to be built in multiple pieces so that the channels could be drilled, with the pieces then welded back together. “3D printing allows you to produce components in a single piece,” Ellis said, “and that’s a huge advantage.”

    Ellis now is designing a steerable mirror for KSTAR that can be controlled by computer to direct microwaves into different parts of the plasma. Ellis dubs this mirror, to be delivered next year, “Generation 2.0,” since it will have flat cooling channels rather than the round ones on the fixed mirror. The flat channels will increase the efficiency of the coolant, he said, which will be important for shedding heat from the constantly moving steerable mirror.

    See the full article here.

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  • richardmitnick 3:35 pm on October 27, 2014 Permalink | Reply
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    From AAAS: “After Election 2014: FUSION RESEARCH” 

    AAAS

    AAAS

    ScienceInsider

    24 October 2014
    Adrian Cho

    Should we stay or should we go? Once the voters have spoken, that’s the question Congress will have to answer regarding the United States’ participation in ITER, the hugely overbudget fusion experiment under construction in Cadarache, France. Some lawmakers say it may be time for the United States to bow out, especially as the growing ITER commitment threatens to starve U.S.-based fusion research programs. The next Congress may have to decide the issue—if the current one doesn’t pull the plug first when it returns to Washington, D.C., for a 6-week lame-duck session.

    ITER Tokamak
    ITER Tokamak

    For those tired of the partisan squabbling on Capitol Hill, the ITER debate may provide curious relief. ITER appears to enjoy bipartisan support in the House of Representatives—and bipartisan opposition among key senators.

    ITER aims to prove that nuclear fusion is a viable source of energy, and the United States has agreed to build 9% of the reactor’s hardware, regardless of the cost. Recent estimates suggest the U.S. price tag could be $3.9 billion or more—nearly quadrupling original estimates and raising alarm among some lawmakers. In response, this past June a Senate appropriations subcommittee proposed a budget bill that would end U.S. participation in the project next year. In contrast, the next month the House passed a bill that would increase U.S. spending on ITER.

    Some observers think the current Congress will kick the issue to the next one by passing a stop-gap budget for fiscal year 2015, which began 1 October, that will keep U.S. ITER going. “I don’t think in the end they can come out and kill ITER based on what the Senate subcommittee did,” says Stephen Dean, president of Fusion Power Associates, a research and educational foundation in Gaithersburg, Maryland. Others say a showdown could come by year’s end.

    Trouble over ITER has been brewing for years. ITER was originally proposed in 1985 as a joint U.S.-Soviet Union venture. The United States backed out of the project in 1998 because of cost and schedule concerns—only to rejoin in 2003. At the time, ITER construction costs were estimated at $5 billion. That number had jumped to $12 billion by 2006, when the European Union, China, India, Japan, Russia, South Korea, and the United States signed a formal agreement to build the device. At the time, ITER was supposed to start running in 2016. By 2011, U.S. costs for ITER had risen to more than $2 billion, and the date for first runs had slid to 2020. But even that date was uncertain; U.S. ITER researchers did not have a detailed cost projection and schedule—or performance baseline—to go by.

    Then in 2013, the Department of Energy (DOE) argued in its budget request for the following year that U.S. ITER was not a “capital asset” and therefore did not have to go through the usual DOE review process for large construction projects—which requires a performance baseline. Even though DOE promised to limit spending on ITER to $225 million a year so as not to starve domestic fusion research efforts, that statement irked Senators Dianne Feinstein (D–CA) and Lamar Alexander (R–TN), the chair and ranking member of the Senate Appropriations Subcommittee on Energy and Water Development, respectively. They and other senators asked the Government Accountability Office (GAO) to investigate the U.S. ITER project.

    This year, things appeared to come to a head. This past April, researchers working on U.S. ITER released their new $3.9 billion cost estimate and moved back the date for first runs to 2024 or later. Two months later, GAO reported that even that new estimate was not reliable and that the cost to the United States could reach $6.5 billion. Based on that report, the Senate energy and water subcommittee moved to kill U.S. ITER in its markup of the proposed 2015 budget, giving it only $75 million for the year, half of what the White House had requested and just enough to wind things down. Alexander supported the move, even though the U.S. ITER office is based in his home state of Tennessee, at Oak Ridge National Laboratory.

    ITER still has friends in the House, however. In their version of the DOE budget for 2015, House appropriators gave ITER $225 million, $75 million more than the White House request. Moreover, the project seems to have bipartisan support in the House, as shown by a hearing of the energy subcommittee of the House Committee on Science, Space, and Technology. Usually deeply divided along party lines, the subcommittee came together to lavish praise on ITER, with representative Lamar Smith (R–TX), chair of the full committee, and Representative Eric Swalwell (D–CA), the ranking member on the subcommittee, agreeing that ITER was, in Swalwell’s words, “absolutely essential to proving that magnetically confined fusion can be a viable clean energy source.” Swalwell called for spending more than $225 million per year on ITER.

    When and how this struggle over ITER plays out depends on the answers to several questions. First, how will Congress deal with the already late budget for next year? The Senate, controlled by the Democrats, has yet to pass any of its 13 budget bills, including the one that would fund energy research. And if the House and Senate decide to simply continue the 2014 budget past the end of the year, then the decision on ITER will pass to the next Congress. If, on the other hand, Congress passes a last-minute omnibus budget for fiscal year 2015, then the fight over ITER could play out by year’s end.

    Second, how sincere is the Senate move to kill ITER? The Senate subcommittee’s move may have been meant mainly to send a signal to the international ITER organization that it needs to shape up, says one Democratic staffer in the House. The international ITER organization received scathing criticism in an independent review in October 2013. That review called for 11 different measures to overhaul the project’s management, and the Senate’s markup may have been meant primarily to drive home the message that those measures had to be taken to ensure continued U.S. involvement, the staffer says.

    Third, how broad is the House’s support for ITER? Over the past decade or so, the House has been more supportive of fusion in general, the Democratic staffer says. But some observers credit that support mainly to one person, Representative Rodney Frelinghuysen (R-NJ), a longtime member of the House Appropriations Committee. “Over the years he’s become a champion of fusion,” Dean says. “He protects it in the House.” Dean and others say that’s likely because the DOE’s sole dedicated fusion laboratory, the Princeton Plasma Physics Laboratory (PPPL), is in his home state of New Jersey (but not Frelinghuysen’s district).

    Indeed, observers say that Frelinghuysen has been instrumental in preventing cuts to the domestic fusion program proposed by DOE itself. For example, for fiscal 2014, DOE requested $458 million for its fusion energy sciences program, including $225 million for ITER. That meant cutting the domestic fusion program by about 20% to $233 million and closing one of three tokamak reactors in the United States. The Senate went along with those numbers, but House appropriators bumped the budget up to $506 million, the number that held sway in the final 2014 spending plan. But some observers speculate that Frelinghuysen might be willing to let ITER go if he could secure a brighter future for PPPL.

    PPPL Tokamak
    PPPL Tokamak

    PPPL NSTX
    PPPL National Spherical Torus Experiment

    Finally, the biggest question surrounding U.S. participation in ITER is: How will the international ITER organization respond to the calls for changes in its management structure? That should become clear within months. So far, officials with U.S. ITER have not been able to produce a baseline cost estimate and schedule in large measure, because the ITER project as a whole does not have a reliable schedule. The international ITER organization has said it will produce one by next July, the House staffer says. And if the international organization doesn’t produce a credible schedule, the staffer says, “the project will be very difficult to defend, even by its most ardent supporters.”

    See the full article here.

    The American Association for the Advancement of Science is an international non-profit organization dedicated to advancing science for the benefit of all people.

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  • richardmitnick 4:29 pm on September 29, 2014 Permalink | Reply
    Tags: , , , , Princeton Plasma Physics Laboratory   

    From PPPL: “PPPL successfully tests system for mitigating instabilities called ‘ELMs’ “ 


    PPPL

    September 29, 2014
    John Greenwald

    PPPL has successfully tested a Laboratory-designed device to be used to diminish the size of instabilities known as “edge localized modes (ELMs)” on the DIII–D tokamak that General Atomics operates for the U.S. Department of Energy in San Diego. Such instabilities can damage the interior of fusion facilities.

    DIII-D
    DIII–D

    The PPPL device injects granular lithium particles into tokamak plasmas to increase the frequency of the ELMs. The method aims to make the ELMs smaller and reduce the amount of heat that strikes the divertor that exhausts heat in fusion facilities.

    The system could serve as a possible model for mitigating ELMs on ITER, the fusion facility under construction in France to demonstrate the feasibility of fusion energy.

    iter tok
    ITER Tokamak

    “ELMs are a big issue for ITER,” said Mickey Wade, director of the DIII-D national fusion program at General Atomics. Large-scale ELMs, he noted, could melt plasma-facing components inside the ITER tokamak.

    General Atomics plans to install the PPPL-designed device, developed by physicist Dennis Mansfield and engineer Lane Roquemore, on DIII-D this fall. Previous experiments using deuterium-injection rather than lithium-injection have demonstrated the ability to increase the ELMs frequency on DIII-D, the ASDEX-Upgrade in Germany and the Joint European Torus in the United Kingdom.

    jet
    Joint European Torus

    Researchers at DIII-D now want to see how the results for lithium-injection compare with those obtained in the deuterium experiments on the San Diego facility. “We want to put them side-by-side,” Wade said.

    PPPL-designed systems have proven successful in mitigating ELMs on the EAST tokamak in Hefei, China, and have been used on a facility operated by the Italian National Agency for New Technologies in Frascati, Italy. A system also is planned for PPPL’s National Spherical Torus Experiment (NSTX), the Laboratory’s major fusion experiment, which is undergoing a $94 million upgrade.

    PPPL NSTX
    PPPL NSTX

    PPPL used salt grain-sized plastic pellets as proxies for lithium granules in testing the system for DIII-D. The pellets fell through a pinhole-sized opening inside a dropper to a rotating high-speed propeller that projected them onto a target precisely as planned.

    Joining Mansfield and Roquemore for the tests were physicists Erik Gilson and Alessandro Bortolon, a former University of Tennessee researcher now at PPPL who will begin an assignment to the DIII-D tokamak at General Atomics this fall. Also participating were Rajesh Maingi, the head of research on edge physics and plasma-facing components at PPPL, and engineer Alexander Nagy, who is on assignment to DIII-D.

    See the full article here.

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

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  • richardmitnick 8:42 pm on September 10, 2014 Permalink | Reply
    Tags: , , , , Princeton Plasma Physics Laboratory,   

    From Princeton: “PPPL scientists take key step toward solving a major astrophysical mystery” 

    Princeton University
    Princeton University

    September 10, 2014
    John Greenwald, Princeton Plasma Physics Laboratory Communications

    PPPL Large

    PPPL

    Magnetic reconnection in the Earth and sun’s atmospheres can trigger geomagnetic storms that disrupt cell phone service, damage satellites and blackout power grids. Understanding how reconnection transforms magnetic energy into explosive particle energy has been a major unsolved problem in plasma astrophysics.

    Scientists at the Princeton Plasma Physics Laboratory (PPPL) and Princeton University have taken a key step toward a solution, as described in a paper published this week in the journal Nature Communications. In research conducted on the Magnetic Reconnection Experiment (MRX) at PPPL, the scientists not only identified how the mysterious transformation takes place, but measured experimentally the amount of magnetic energy that turns into particle energy. This work was supported by the U.S. Department of Energy’s Office of Science.

    Magnetic field lines represent the direction, and indicate the shape, of magnetic fields. In magnetic reconnection, the magnetic field lines in plasma snap apart and violently reconnect. The MRX, built in 1995, allows researchers to study the process in a controlled laboratory environment.
    Reconnecting field lines

    lines
    This fast-camera image shows plasma during magnetic reconnection, with magnetic field lines rendered in white based on measurements made during the experiment. The converging horizontal lines represent the field lines prior to reconnection. The outgoing vertical lines represent the field lines after reconnection. (Image by Jongsoo Yoo, Princeton Plasma Physics Laboratory)

    The new research shows that reconnection converts about 50 percent of the magnetic energy, with one-third of the conversion heating the electrons and two-thirds accelerating the ions — or atomic nuclei — in the plasma. In large bodies like the sun, such converted energy can equal the power of millions of tons of TNT.

    “This is a major milestone for our research,” said Masaaki Yamada, a research physicist, the principal investigator for the MRX and first author of the Nature Communications paper. “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 proto-typical reconnection layer.”

    The findings also suggested the process by which the energy conversion occurs. Reconnection first propels and energizes the electrons, according to the researchers, and this creates an electrically charged field that “becomes the primary energy source for the ions,” said Jongsoo Yoo, an associate research physicist at PPPL and co-author of the paper.

    The other contributors to the paper were Hantao Ji, professor of astrophysical sciences at Princeton; Russell Kulsrud, professor of astrophysical sciences, emeritus, at Princeton; and doctoral candidates in astrophysical sciences Jonathan Jara-Almonte and Clayton Myers.

    If confirmed by data from space explorations, the PPPL results could help resolve decades-long questions and create practical benefits. These could include a better understanding of geomagnetic storms that could lead to advanced warning of the disturbances and an improved ability to cope with them. Researchers could shut down sensitive instruments on communications satellites, for example, to protect the instruments from harm.

    Next year NASA plans to launch a four-satellite mission to study reconnection in the magnetosphere — the magnetic field that surrounds the Earth. The PPPL team plans to collaborate with the venture, called the Magnetospheric Multiscale (MMS) Mission, by providing MRX data to it. The MMS probes could help to confirm the laboratory’s findings.

    four
    All four MMS spacecraft are stacked and ready for transport to the vibration chamber for environmental tests. Although they will be disassembled again later this month, this image is a sneak preview of what will be the final flight configuration of the MMS fleet.

    PPPL, on Princeton University’s Forrestal Campus in Plainsboro, New Jersey, 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. Fusion takes place when atomic nuclei fuse and release a burst of energy. This compares with the fission reactions in today’s nuclear power plants, which operate by splitting atoms apart.

    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 single largest 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.

    See the full article here.

    About Princeton: Overview

    Princeton University is a vibrant community of scholarship and learning that stands in the nation’s service and in the service of all nations. Chartered in 1746, Princeton is the fourth-oldest college in the United States. Princeton is an independent, coeducational, nondenominational institution that provides undergraduate and graduate instruction in the humanities, social sciences, natural sciences and engineering.

    As a world-renowned research university, Princeton seeks to achieve the highest levels of distinction in the discovery and transmission of knowledge and understanding. At the same time, Princeton is distinctive among research universities in its commitment to undergraduate teaching.

    Today, more than 1,100 faculty members instruct approximately 5,200 undergraduate students and 2,600 graduate students. The University’s generous financial aid program ensures that talented students from all economic backgrounds can afford a Princeton education.

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  • richardmitnick 4:53 pm on August 28, 2014 Permalink | Reply
    Tags: , , Princeton Plasma Physics Laboratory   

    From PPPL: “PPPL lends General Electric a hand in developing an advanced power switch” 


    PPPL

    August 28, 2014
    John Greenwald

    Scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) are assisting General Electric Co. in developing an electrical switch that could help lower utility bills. The advanced switch “could contribute to a smarter, more advanced, more reliable, and more secure electric grid,” according to the DOE’s Advanced Research Projects Agency-Energy (ARPA-E), which is funding the GE project.

    switch
    Laboratory test of a liquid-metal cathode. (Photo by General Electric Co.)

    The company is drawing upon PPPL’s know-how in dealing with plasma, the hot, electrically charged gas that researchers control with magnetic fields to fuel fusion reactions. Plasma will form the heart of the proposed GE device, which would use a plasma-filled tube to switch electricity on and off in power-conversion systems.

    This gas-filled tube would replace the bulky and costly assemblies of semiconductor switches now used in systems that convert the direct current (DC) coming from long-distance power lines to the alternating current (AC) that lights homes and businesses. Such systems also convert AC current to DC current for transmission between AC power grids.

    GE is turning to PPPL for help with these tasks:

    • Modeling plasma properties for different magnetic-field configurations and gas pressures. “There aren’t many places with a demonstrated ability to model this type of plasma,” said Timothy Sommerer a physicist at GE Global Research Center who heads the switch project. “These guys [at PPPL] really came through and said they could do it.”

    • Developing a method for protecting the cathode — the negative terminal inside the plasma-filled tube — from damage from the positively charged ions, or atomic nuclei, in the dense current that flows through the gas. “You need to operate above a certain current density,” Sommerer said. “But this leads to ion impact that can damage the cathode. So what you want is high current-density and low cathode-damage.”

    Sommerer has tapped a team led by physicist Igor Kaganovich, deputy head of the PPPL Theory Department, for the modeling task. The team employs specially designed codes to simulate the plasma, said Kaganovich, who works with physicists Alexander Khrabrov and Johan Carlsson on the project. Joining them for the summer were students Mikhail Khodak of Princeton University and David Keating of the University of California-Berkeley.

    For tips on protecting the cathode, GE has been studying PPPL’s use of liquid lithium to prevent damage to the divertor that exhausts heat in fusion facilities. The flowing liquid metal forms a wet, self-healing barrier that constantly replenishes itself, said physicist Michael Jaworski, an expert on the use of lithium in fusion experiments.

    GE is working with cathodes made of liquid gallium for its self-healing properties. Learning of PPPL’s work with liquid lithium was “just serendipitous,” Sommerer said, since GE initially sought the Laboratory’s plasma-modeling skills. But “conditions in the divertor are pretty similar to what the cathode would face,” he noted, making PPPL’s experience quite useful to know.

    For tips on protecting the cathode, GE has been studying PPPL’s use of liquid lithium to prevent damage to the divertor that exhausts heat in fusion facilities. The flowing liquid metal forms a wet, self-healing barrier that constantly replenishes itself, said physicist Michael Jaworski, an expert on the use of lithium in fusion experiments.

    GE is working with cathodes made of liquid gallium for its self-healing properties. Learning of PPPL’s work with liquid lithium was “just serendipitous,” Sommerer said, since GE initially sought the Laboratory’s plasma-modeling skills. But “conditions in the divertor are pretty similar to what the cathode would face,” he noted, making PPPL’s experience quite useful to know.

    See the full article here.

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

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  • richardmitnick 12:19 pm on July 15, 2014 Permalink | Reply
    Tags: , , , , , Princeton Plasma Physics Laboratory   

    From PPPL: “Experts assemble at PPPL to discuss mitigation of tokamak disruptions” 


    PPPL

    July 15, 2014
    John Greenwald

    Some 35 physicists from around the world gathered at PPPL last week for the second annual Laboratory-led workshop on improving ways to predict and mitigate disruptions in tokamaks. Avoiding or mitigating such disruptions, which occur when heat or electric current are suddenly reduced during fusion experiments, will be crucial for ITER the international experiment under construction in France to demonstrate the feasibility of fusion power.

    two
    Amitava Bhattacharjee, left, and John Mandrekas, a program manager in the U.S. Department of Energy’s office of Fusion Energy Sciences.(Photo by Elle Starkman/Princeton Office of
    Communications )

    PPPL Tokamak
    Tokamak at PPPL

    Presentations at the three-day session, titled “Theory and Simulation of Disruptions Workshop,” focused on the development of models that can be validated by experiment. “This is a really urgent task for ITER,” said Amitava Bhattacharjee, who heads the PPPL Theory Department and organized the workshop. The United States is responsible for designing disruption-mitigation systems for ITER, he noted, and faces a deadline of 2017.

    Speakers at the workshop included theorists and experimentalists from the ITER Organization, PPPL, General Atomics and several U.S. Universities, and from fusion facilities in the United Kingdom, China, Italy and India. Topics ranged from coping with the currents and forces that strike tokamak walls to suppressing runaway electrons that can be unleashed during experiments.

    Bringing together theorists and experimentalists is essential for developing solutions to disruptions, Bhattacharjee said. “I already see that major fusion facilities in the United States, as well as international tokamaks, are embarking on experiments that are ideal validation tools for theory and simulation,” he said. “And it is very important that theory and simulation ideas that can be validated with experimental results are presented and discussed in detail in focused workshops such as this one.”

    See the full article here.

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


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