Evidence for the Importance of Trapped Particle Resonances for Resistive Wall Mode Stability in High Beta Tokamak Plasmas

H. Reimerdes, J. W. Berkery, M. J. Lanctot, A. M. Garofalo, J. M. Hanson, Y. In, M. Okabayashi, S. A. Sabbagh, and E. J. Strait

Phys. Rev. Lett. 106, 215002 – Published 23 May 2011

Abstract

Active measurements of the plasma stability in tokamak plasmas reveal the importance of kinetic resonances for resistive wall mode stability. The rotation dependence of the magnetic plasma response to externally applied quasistatic $n = 1$ magnetic fields clearly shows the signatures of an interaction between the resistive wall mode and the precession and bounce motions of trapped thermal ions, as predicted by a perturbative model of plasma stability including kinetic effects. The identification of the stabilization mechanism is an essential step towards quantitative predictions for the prospects of “passive” resistive wall mode stabilization, i.e., without the use of an “active” feedback system, in fusion-alpha heated plasmas.

Received 21 December 2010

DOI:https://doi.org/10.1103/PhysRevLett.106.215002

Authors & Affiliations

H. Reimerdes^1,*, J. W. Berkery¹, M. J. Lanctot^1,†, A. M. Garofalo², J. M. Hanson^1,3, Y. In⁴, M. Okabayashi⁵, S. A. Sabbagh¹, and E. J. Strait²

¹Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027-6902, USA
²General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
³Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831, USA
⁴FAR-TECH, Inc., 3550 General Atomics Court, San Diego, California 92121, USA
⁵Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543-0451, USA

^*Present address: CRPP-EPFL, Lausanne, Switzerland.
^†Present address: LLNL, Livermore, CA, USA.