Collisional Effects on the Drift Hole Dynamics in Magnetically Confined Plasmas

Abstract

The effect of collisions on the dynamics of phase space structures in inhomogeneous magnetized plasmas is analyzed. A drift hole is used as an example, and subcritical bifurcation associated with a drift hole is analyzed in the presence of small but finite collisional damping. It is shown that there exists a critical collisionality, below which finite amplitude turbulent state can be sustained even in the absence of linear instability. This gives a crude estimate on how “collisionless” is collisionless for nonlinear dynamics of phase space structures to appear.