Plasma

Most Potent Tool in Fusion Science

Written by Tim Lash, Focus Fusion Society Contributor. There are a pair of stories highlighting the importance of computer simulation for fusion science. Fusion research is expensive. Big reactors require large quantities of costly materials. Construction projects run for years or decades. Ramp up times necessitate huge investments before the science can even begin. Hence the usefulness of computer simulation. Careful modeling of reactor design or plasma behavior can yield insights that save time and money while inching us closer to clean fusion power. Therefore, computers are often the most valuable tool to the fusion scientist. The first story describes simulation of plasma turbulence. Researchers used multi-scale simulations to study turbulent instabilities that cause plasma heat loss. The simulation added […]

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Wendelstein 7-X Stellarator Restarting

Written by Tim Lash, Focus Fusion Society Contributor. The Wendelstein 7-X stellarator reactor at Greifswald is restarting for a second round of experiments. These tests are slated for higher temperatures now that reactor modifications are complete. The reactor changes will also allow for longer plasma confinement times. An important goal of this round of experimentation centers on the proper functioning of ten plasma divertors. After an initial round of shakedown tests, the Wendelstein 7-X went offline last year. This downtime allowed for more construction to take place. Upgrades to instrumentation occurred. The metal walls of the reaction chamber were lined with over 8,000 graphite tiles. These tiles protect the metal walls from the extreme plasma temperatures. The tiles will allow […]

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LPP Fusion News

Written by Tim Lash, Focus Fusion Society Contributor. LPP Fusion recently released a newsletter. The letter outlined three items and gave insight into the research program for the balance of 2017. News of a new cathode along with reactor data analysis and maintenance updates were included. The most significant news was the arrival of a new beryllium cathode. A beryllium anode was received earlier in the year. With both in hand, plans for swapping out the current tungsten terminals can proceed. The balance of September will see some final testing with these tungsten electrodes. Then disassembly of the vacuum chamber will begin. The reaction chamber will receive a fresh titanium coating and have the electrodes changed out. “We expect that […]

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Liquid Metal Fusion Reactors

Written by Tim Lash, Focus Fusion Society Contributor. One of the most challenging aspects of sustainable fusion power are the high temperatures required. These high temperatures stress any imagined containment device. Researchers from the Netherlands Organisation for Scientific Research (NWO) tested a containment model lined with liquid metal. They believe such an approach could improve dealing with the severe temperature gradients of fusion plasma. Their findings are documented in an article published in the journal Nature. A plasma reactor trying to sustain fusion is a very corrosive environment. Solid reactor walls and any equipment in proximity to the plasma will become degraded over time. Metallic parts become pitted and brittle with prolonged plasma exposure. Refreshing the liquid metal in this […]

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Optimizing Plasma

Written by Tim Lash, Focus Fusion Society Contributor. Lawrenceville Plasma Physics fusion research has aneutronic hydrogen-boron fueled fusion as its energy production goal. Another fusion project that proposes to use hydrogen-boron fuel takes a clever approach to finding a hot plasma regime. Tri Alpha Energy (TAE) is building a colliding beam fusion reactor. A recent article published in the journal Science Reports outlines a high tech approach to optimize the operating characteristics of their device. By its very nature producing energy via fusion is complex. The science can be daunting, and the machines that attempt to achieve fusion incredibly intricate. These machines generally have a multitude of operating parameters that need to be tuned and calibrated. Response to input parameters […]

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A Shift in Energy Needs to Include Fusion(Part One)

Pictures of energy technologies in the present and near future. Written by Mark Nelson. On June 13, 2017, Stanford University futurist Tony Seba gave a presentation at the Colorado Renewable Energy Society(CRES). He predicts a 13-year ramp up of solar power, autonomous electric vehicles, and large energy storage capacities, all with decreasing prices in the market. This convergence of technologies will cause a disruption in our transportation and energy systems. He presents his case in a YouTube video here. He says it will also disrupt our economic systems, just as the internet, the cell phone, and the adoption of business models have changed the speed of communication. Mr. Seba uses historical references, and a leverage of data trends, asking the […]

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Taming Runaway Electrons from Fusion Plasma

Written by Tim Lash, Focus Fusion Society Contributor. Edited by Ignas Galvelis, Supervising Director. A team of European scientists has published findings revealing a better understanding of plasma dynamics allowing tokamak designs to take another step forward. In tokamak reactors, a catastrophic effect can occur known as runaway electrons. In these scenarios, free electrons in the plasma can form coherent currents of as much as one million amperes. These electron currents have the potential to breach the plasma containment fields and cause serious damage to the reactor. In a recent Letter to Physical Review, the team describe a method for countering such rogue currents thereby protecting the reactor from damage. Their method entails injecting neon (atomic number 10) or argon […]

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Simulation of L-mode to H-mode Plasma Transition

Written by Tim Lash, Focus Fusion Society Contributor. Edited by Ignas Galvelis, Supervising Director. After 6.3 sextillion (6.3×10^21) CPU cycles of the Titan super computer running at the Oak Ridge Leadership Computing Facility (OLCF), a team of researchers has successfully simulated the spontaneous transition of turbulence at the edge of a fusion plasma from low confinement mode (L-mode) magnetic containment to high confinement mode (H-mode).  It took three days for Titan to run this simulation.  The simulation itself was modeling a mere 270 microseconds of real time plasma behavior. U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) physicists utilized 90 percent of Titan’s capacity during that three-day time-slot.  The Titan machine is the nation’s most powerful supercomputer for […]

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