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PPPL researchers advance understanding of plasma turbulence that drains heat from fusion reactors
http://www.pppl.gov/news/2016/02/pppl-researchers-advance-understanding-plasma-turbulence-drains-heat-fusion-reactors[font face=Serif][font size=5]PPPL researchers advance understanding of plasma turbulence that drains heat from fusion reactors[/font]
By Raphael Rosen
February 22, 2016
[font size=3]The life of a subatomic particle can be hectic. The charged nuclei and electrons that zip around the vacuum vessels of doughnut-shaped fusion machines known as tokamaks are always in motion. But while that motion helps produce the fusion reactions that could power a new class of electricity generator, the turbulence it generates can also limit those reactions.
Now, physicists at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) appear to have gained important new insights into what affects this turbulence, which can impact the leakage of heat from the fusion plasma within tokamaks. Understanding how fusion plasmas lose heat is crucial because the more a plasma is able to retain its heat the more efficient a fusion reactor can be. Such understanding could improve the performance of ITER, the multinational tokamak being built in France, by leading to a reduction in heat leakage.
…
This contribution was demonstrated in multiscale simulations, led by MIT research scientist Nathan Howard, that contradicted a common assumption that the impact of electrons was virtually negligible in conventional tokamaks. The separate Ruiz research provided further evidence of the importance of electrons to the turbulent transport of plasma. The spherical tokamak this research was based on enables the impact of electrons to be more readily seen, since the much larger ion-scale turbulence in such tokamaks is usually suppressed.
"Understanding the stabilizing mechanisms of the turbulence is definitely an important task in order to gain a predictive capability in the design of future fusion reactors," said Ruiz. "Further investigation is required to understand heat losses in tokamaks, and the upgraded version of the NSTX, the NSTX-U, will certainly be used to investigate this issue in detail."
…[/font][/font]
By Raphael Rosen
February 22, 2016
[font size=3]The life of a subatomic particle can be hectic. The charged nuclei and electrons that zip around the vacuum vessels of doughnut-shaped fusion machines known as tokamaks are always in motion. But while that motion helps produce the fusion reactions that could power a new class of electricity generator, the turbulence it generates can also limit those reactions.
Now, physicists at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) appear to have gained important new insights into what affects this turbulence, which can impact the leakage of heat from the fusion plasma within tokamaks. Understanding how fusion plasmas lose heat is crucial because the more a plasma is able to retain its heat the more efficient a fusion reactor can be. Such understanding could improve the performance of ITER, the multinational tokamak being built in France, by leading to a reduction in heat leakage.
…
This contribution was demonstrated in multiscale simulations, led by MIT research scientist Nathan Howard, that contradicted a common assumption that the impact of electrons was virtually negligible in conventional tokamaks. The separate Ruiz research provided further evidence of the importance of electrons to the turbulent transport of plasma. The spherical tokamak this research was based on enables the impact of electrons to be more readily seen, since the much larger ion-scale turbulence in such tokamaks is usually suppressed.
"Understanding the stabilizing mechanisms of the turbulence is definitely an important task in order to gain a predictive capability in the design of future fusion reactors," said Ruiz. "Further investigation is required to understand heat losses in tokamaks, and the upgraded version of the NSTX, the NSTX-U, will certainly be used to investigate this issue in detail."
…[/font][/font]
