ANOMALOUS PARTICLE AND ELECTRON-ENERGY PINCHES

Interest in plasma pinches has recently increased due to the observation in electron cyclotron heated (ECH) plasmas in the Doublet III-D (DIII-D) tokamak [Plasma Physics and Controlled Nuclear Fusion Research, 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. I, p. 159] of an electron energy pinch. Previous work on drift wave-induced particle and electron energy pinches concluded that they were only possible in strictly collisionless plasmas, nu* = 0, an assumption not applicable to electron-cyclotron heating experiments. In the present work it is shown that a more detailed quasilinear analysis predicts a particle pinch at moderate collisionality, nu* = 0.2 to 1.0, when the electron temperature gradient parameter eta(e) is in the range eta(e) = 2 to 3. Further, the quasilinear analysis is expanded to include the effects of turbulent resonance broadening on the circulating electrons. It is then found that, in addition to a particle pinch (qualitatively the same as the quasilinear prediction), a simultaneous particle and electron energy pinch at moderate collisionality can occur at eta(e) congruent-to 1, which is lower than in ECH experiments where eta(e) = 2 to 3.