Linear stability of high-m drift-tearing modes

Abstract

A new model for the electron parallel conductivity in a plasma of moderate collisionality is formulated using the Williamson collision operator. With this model, the linear stability of high‐m drift‐tearing modes (driven unstable by ∇T_e) is studied as a function of the electron‐ion collision frequency ν_c with no restriction placed on the ratio ν_c/ω. It is shown that the growth rate of this instability can be substantial for realistic tokamak parameters. The implication for understanding the observed magnetic turbulence and anomalous electron heat transport in tokamaks is discussed.