Perturbation of a Wave Field by an Irregularity in a Magneto-Plasma
When a satellite is in an environment such that the order of the Debye length exceeds the lengths of the aerials or booms, the wave field which is recorded may be perturbed by the irregularity of plasma around the satellite. This may happen, for example, in a satellite such as GEOS. The region of non-uniformity may be electron-depleted at night, or electron-enhanced during the day. In order to study the qualitative effects of an irregularity on an incident wave field we have formulated an idealized model. In the simplified problem, electromagnetic radiation propagating through a cold magneto-plasma falls upon an irregularity in the form of an ellipsoid of different density whose axis is parallel to the unperturbed magnetic field. This idealization is treated in the quasi-static approximation. We use spheroidal coordinates, which have previously been successful in dealing with the problem of an evacuated cavity in a magneto-plasma. The results show that the wave field is perturbed in both amplitude and phase within the irregularity and its neighborhood. Some of the resonances found in the case of a cavity now disappear. The longitudinal and split transverse Tonks-Langmuir resonances still remain, but become separated in frequency when the ellipsoid varies from the spherical shape.
KeywordsWave Field Debye Length Isotropic Case Legendre Function Split Resonance
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