Transport equations on different time scales for intermediately and strongly collislonal regimes

摘要

The plasma transport equations for a weakly colliaional plasma have previously been derived for four different time scales. This paper is devoted to the derivation of the plasma transport equations for the two other complementary regimes: the intermediately collisional regime (IOR) (i.e. for the case where the transit time to -1 is of the same order as the collision time v-l, w-1≈v-1), and the strongly collisional regime (SCR) (i.e. for the case of a>-1 v-*) for different time scales. It is shown that the lowest-order gyromotion is unperturbed by collisions. On the Alfven time scale, one merely obtains for both the intermediately collisional case and the strongly collisional case the single-fluid ideal MHD equations, if certain additional requirements are satisfied, On the MHD-collision time scale, one arrives at the full set of transport equations, where in both cases, contrary to the weakly collisional case, no turbulent terms are found. On the resistive diffusion timescale, one ends up with the known transport equations, with the addition of turbulent contributions.