Unified fluid/kinetic description of plasma microinstabilities. Part II: Applications

Abstract

The unified fluid/kinetic equations developed in Part I [Phys. Fluids B 4, ▪▪▪ (1992)] of this work are used to study plasma-drift-type microinstabilities. A generalized perturbed Ohm’s law is derived (for a sheared slab magnetic field model) that is uniformly valid for arbitrary collisionality ω/ν and adiabaticity ω/k∥vt. Applications to electron drift waves, ion temperature gradient modes (ηi modes) and electron electromagnetic modes (microtearing modes) are addressed. It is shown that the unified equations exhibit their simple and uniformed features in the plasma microinstability analysis. The well-known results of these instability branches in both fluid and adiabatic limits are easily recovered using the new fluid/kinetic equations. Generalization of the two-field Hasegawa–Wakatani turbulent equations [Phys. Rev. Lett. 50, 682 (1983)] to include electron temperature fluctuations and linear Landau damping effects is also discussed. Finally, a new method is presented to facilitate the study of magnetic trapped particle modes using the present kinetic closure procedure. It is found that by including the trapped particle effects in the closure relations, the usual separation of the fluid equations into trapped and untrapped components becomes unnecessary.

Heat diffusion across magnetic islands and ergodized plasma regions in realistic tokamak geometry

“…Chang and Callen derived L Ϸ 1 / ͉k ʈ ͉ with a theoretical approach, where k ʈ denotes the parallel wave number. 7,8 This length scale is comparable to the distance along a field line between the poloidal positions of the island x-and o-points. We apply the heat flux limit ͑HFL͒ correction using the analytical matching…”

Electron parallel transport for arbitrary collisionality

“…[6,7]. The transport relations can be used to close the electron fluid system of density (n), and temperature (T ) when the ion flow velocity is provided by the ion fluid equations.…”

Landau fluid model for weakly nonlinear dispersive magnetohydrodynamics

“…A more recent development, the Chapman-Enskog-like approach [10,11], allows to express the closure relations in terms of the lower-order fluid moments (typically velocities and temperatures) like in Braginskii's relations but taking into account the nonlocal operators at the origin of Landau damping, in a way consistent with the so-called Landau fluid approach [12,1]. This approach is appropriate for the inclusion of an arbitrary amount of collisions.…”