DETERMINATION OF MAGNETOSPHERIC PLASMA DENSITY BY USE OF LONG-PERIOD GEOMAGNETIC MICROPULSATIONS

A new method is presented of determining the magnetospheric plasma density distribution, using long period geomagnetic micropulsations (period 45-600 sec.). Long period micropulsations are assumed to be caused by resonant oscillations of geomagnetic lines of force in the magnetosphere. Eliminating the time dependent factor from the wave equations leads to an ordinary differential equation that depends on a spatial parameter only. With certain boundary conditions assigned beforehand (which may be determined by observation), the differential equation uniquely determines the ‘spatial form’ of the oscillation if the plasma density distribution is known. A distribution is determined so that the spatial form is that of the fundamental and of the second harmonic, since these modes are the most likely to be excited. Results are compared with other investigations-good agreement is obtained with those from the IMP II satellite. © 1968, Society of Geomagnetism and Earth, Planetary and Space Sciences. All rights reserved.