Kinetic toroidal Alfven eigenmodes in finite-beta tokamak plasmas

摘要

Kinetic toroidal Alfven eigenmodes (KTAEs) in finite-beta circular tokamak plasmas art: investigated. Here, beta is the ratio between plasma and magnetic pressures, and, formally, beta similar to O(r/Rq(2)), with q being the safety factor, r and R denoting, respectively, minor and major radii. A new effect associated with finite parallel electric field effect due to the ion magnetic drift (IMD) is discovered, which is of the same order as that due to the well-known effect associated with the finite ion Larmor radii. The IMD-induced parallel electric field effect is shown to contribute to potential wells for the eigenmodes. Therefore, the IMD-induced parallel electric held effect can discretize the lower Alfven continuum along the real eigenfrequency. Subsequently, this new branch of KTAEs could be readily destabilized by the energetic ions. (C) 1998 American Institute of Physics. [References: 26]