Kinetic Modifications to MHD Phenomena in Toroidal Plasmas
Authors: C.Z. Cheng, N.N. Gorelenkov, G.J. Kramer and E. Fredrickson
Date of PPPL Report: September 2004
Presented at: the Joint Varenna-Lausanne International Workshop on the Theory of Fusion Plasmas, Varenna, Italy, 30 August-3 September 2004; proceedingsto be published in the book series "Theory of Fusion Plasmas."
Particle kinetic effects involving small spatial and fast temporal scales can strongly affect MHD phenomena and the long time behavior of plasmas. In particular, kinetic effects such as finite ion gyroradii, trapped particle dynamics, and wave-particle resonances have been shown to greatly modify the stability of MHD modes. Here, the kinetic effects of trapped electron dynamics and finite ion gyroradii are shown to have a large stabilizing effect on kinetic ballooning modes in low aspect ratio toroidal plasmas such as NSTX [National Spherical Torus Experiment]. We also present the analysis of Toroidicity-induced Alfvén Eigenmodes (TAEs) destabilized by fast neutral-beam injected ions in NSTX experiments and TAE stability in ITER due to alpha-particles and MeV negatively charged neutral beam injected ions.