Suppressed ion-scale turbulence in a hot high-β plasma
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Received 21 Aug 2015 | Accepted 7 Nov 2016 | Published 21 Dec 2016 DOI: 10.1038/ncomms13860 OPEN
Suppressed ion-scale turbulence in a hot high-b plasma
L. Schmitz1,2, D.P. Fulton2, E. Ruskov3, C. Lau3, B.H. Deng2, T. Tajima2,3, M.W. Binderbauer2, I. Holod3, Z. Lin3, H. Gota2, M. Tuszewski2, S.A. Dettrick2 & L.C. Steinhauer2
An economic magnetic fusion reactor favours a high ratio of plasma kinetic pressure to magnetic pressure in a well-confined, hot plasma with low thermal losses across the confining magnetic field. Field-reversed configuration (FRC) plasmas are potentially attractive as a reactor concept, achieving high plasma pressure in a simple axisymmetric geometry. Here, we show that FRC plasmas have unique, beneficial microstability properties that differ from typical regimes in toroidal confinement devices. Ion-scale fluctuations are found to be absent or strongly suppressed in the plasma core, mainly due to the large FRC ion orbits, resulting in near-classical thermal ion confinement. In the surrounding boundary layer plasma, ion- and electron-scale turbulence is observed once a critical pressure gradient is exceeded. The critical gradient increases in the presence of sheared plasma flow induced via electrostatic biasing, opening the prospect of active boundary and transport control in view of reactor requirements.
    1 Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA. 2 Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA. 3 Department of Physics and Astronomy, University of California, Irvine, Irvine, California 92697, USA. Correspondence and requests for materials should be addressed to L.S. (email:
NATURE COMMUNICATIONS | 7:13860 | DOI: 10.1038/ncomms13860 | 1

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