WHISTLER WAVES GENERATION AND CURRENT CLOSURE BY A PULSED TETHER IN IONOSPHERIC PLASMAS

The dynamics response of ionospheric plasmas is modeled for current so urces induced by a pulsed tether. A new method was developed which com bines analytic and numerical techniques to study the dynamic response of a 2-D magnaetoplasma to a time-dependent current source imposed acr oss the magnetic field. The set of cold electron/ion plasma equations and Maxwell's equations are first solved analytically in (k, w) space. Inverse Laplace and 2-D complex Fast Fourier Transform (FFT) techniqu es are subsequently used to numerically transform the radiation fields and plasma currents from (k, w) space to (r, t) space. These results show that ionospheric plasmas respond to current sources induced by a pulsed tether through the excitation of whistler waves and formation o f an expanding local current loop, induced by field-alinged plasma cur rents. The current loop consists of two-anti-parallel field-aligned cu rrent channels concentrated at the ends of the imposed tether current and a cross-field current region connecting these channels. The latter currents are driven by an electron Hall drift. Copyright (C) 1996 Els evier Science Ltd