Propagation of a transient electromagnetic disturbance in an inhomogeneous, collisional, Magnetized plasma

Abstract

The time response of an anisotropic, inhomogeneous magnetized plasma to a time-dependent externally applied electric field is studied. The plasma is considered as a conducting medium embedded in a static magnetic field Bo, with finite and constant parallel conductivity σ∥ and normal conductivity σ⊥ exponentially varying; a constant ion polarization conductivity (σpol) normal to B0 is also included. The driving term E0 is assumed to be normal to the ambient magnetic field, with a space dependence only in the (E0, B0)-plane (two-dimensional case). The problem is treated as an initial (in time) and boundary (in space) value problem, and an analytic solution is obtained for the time response of the system to a unit step of electric field; the solution for any other driving field is then given via a convolution integral. This model can be used in particular to study the propagation through the ionosphere of ULF waves generated by the motion of an artificially created ion cloud in the upper F region. Moreover, the mathematical technique is rather general, so it may be used also for different plasma models. © 1987 Società Italiana di Fisica.