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Stabilization of the tearing mode by turbulent diffusion and runaway electrons

Technical Report ·
OSTI ID:5410220

A fully kinetic analysis of the m = 2 tearing mode is performed for a tokamak plasma including the effects of turbulent electron diffusion and runaway electrons. Turbulent diffusion is included in the analysis of applying the normal stochastic approximation (NSA) to the collisionless drift kinetic equation (DKE) for electrons. A kinetic analysis inherently allows for the choice of various equilibrium electron velocity distributions, thus enabling a comparison between a drifted Maxwellian and a runaway-type distribution. This analysis is fully electromagnetic, including the effects a magnetic fluctuation potential A/sub vertical bars/ as well as a finite electrostatic potential phi, and is valid in the low-beta, low-frequency regime. The electron response is obtained by applying the NSA to the DKE, and the ion response is given by the linearized Vlasov equation. Ampere's law and quasineutrality are then used to derive a set of coupled, self-adjoint equations for the fluctuation potentials phi and A/sub vertical bars/. Solutions to this set of equations describe both unstable finite-..beta.. drift waves when analyzed for high m modes and the tearing mode when analyzed for low m modes (where m is the poloidal mode number).

Research Organization:
Massachusetts Inst. of Tech., Cambridge (USA). Plasma Fusion Center
DOE Contract Number:
AC02-78ET51013
OSTI ID:
5410220
Report Number(s):
DOE/ET/51013-190; PFC/RR-86-18; ON: DE86014665
Country of Publication:
United States
Language:
English