(1) Institute of General Physics, Russian Academy of Sciences, 117942 Moscow, Russia;(2) CIEMAT, Madrid
Abstract:
The results of an experimental study of the influence of unstable MHD modes on plasma confinement in an L-2M stellarator are
presented. The spectral and statistical characteristics of turbulent plasma simultaneously at both the edge and center of
the plasma are investigated. It is shown that at constant power of electron-cyclotron heating of the plasma the energy content
of the plasma depends strongly on the strength of the externally applied vertical magnetic field used to adjust the position
of the plasma column. Appreciable degradation of plasma confinement is observed for values of the vertical field such that
ideal MHD modes become unstable in the greater part of the plasma column. This in turn is due to the formation of a magnetic
configuration with a magnetic “hump.” At the same time, in the edge plasma the instability of resistive-balloon modes grows,
and turbulent particle transport increases.
Pis’ma Zh. éksp. Teor. Fiz. 69, No. 6, 407–412 (25 March 1999)