Low frequency propagation in the Earth's magnetosphere

Abstract

Our principal conclusion is that large orbital radii will be required for imaging at 1.5 MHz. The minimum radius has not been determined, but it is at least 2.5R_⊕ under conditions of solar maximum. Successful imaging from within the plasmasphere may depend upon the feasibility of correction schemes.

Clearly, much more extensive calculations are required, particularly for large radii, both propagation modes, and over a wide range of zenith angles. The magnetosphere should be modelled under both solar minimum and solar maximum conditions, and with a plasmapause and magnetotail. In addition, various possible correction schemes need to be considered in detail, and possibly simulated.

Finally, we note that considerations such as these need to be applied to the solar wind. It is of course recognized that scattering by irregularities will broaden compact sources and ultimately limit the resolution (Dennison and Booth 1987; Spangler 1990). In addition however, large-scale interplanetary refraction and the resulting distortion needs to be evaluated.