Computer simulation of ionospheric radio frequency heating.

摘要

Linear and nonlinear absorption of electromagnetic waves in a warm, magnetized, nonuniform plasma is studied using an electromagnetic particle simulation code (ZOHAR) with either 1 or 2 spatial and 3 velocity dimensions. With fixed ions, finite temperature, and finite wave amplitude, transmission of the ordinary mode to the slow extraordinary wave (Z mode) is found to agree with cold plasma theory for linear conversion, and interference of mode converted waves is observed. With mobile ions and a parabolic density profile which peaks at the critical layer ((omega)(sub p) = (omega)), the wave electric field is enhanced (factor of ten or more) near the critical layer where the wave becomes electrostatic, and small-scale density fluctuations (cavitons) are observed ((delta)(ell) (approx) 10(lambda)(sub D); (delta)n/n (approx) 0.1), typical of strong Langmuir turbulence. Wave damping and particle acceleration are also observed. Application to ionospheric heating is discussed. 15 refs., 23 figs., 1 tab.