Propagation and growth of whistler mode waves generated by electron beams in Earth's bow shock. Progress report
In this study, the propagation and growth of whistler mode waves generated by electron beams within Earth's bow shock is investigated using a planar model for the bow shock and a model electron distribution function. Within the shock, the model electron distribution function possesses a field-aligned T > T beam that is directed toward the magnetosheath. Waves with frequencies between about 1 and 100 Hz with a wide range of wave normal angles are generated by the beam via Landau and anomalous cyclotron resonances. However, because the growth rate is small and because the wave packets traverse the shock quickly, these waves do not attain large amplitudes. Waves with frequencies between about 30 and 150 Hz with a wide range of wave normal angles are generated by the beam via the normal cyclotron resonance. The ray paths for most of these waves are directed toward the solar wind although some wave packets, due to plasma convection travel transverse to the shock normal. These wave packets grow to large amplitudes because they spend a long time in the growth region. The results suggest that whistler mode noise within the shock should increase in amplitude with increasing upstream theta sub Bn. The study provides an explanation for the origin of much of the whistler mode turbulence observed at the bow shock.
- Research Organization:
- Iowa Univ., Iowa City (USA). Dept. of Physics and Astronomy
- OSTI ID:
- 6046203
- Report Number(s):
- AD-A-145572/4
- Resource Relation:
- Other Information: Sponsored in part by Grant NGL-16-001-043
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
MAGNETOSPHERE
WHISTLERS
ELECTRON BEAMS
MAGNETOSHEATH
RADIOWAVE RADIATION
WAVE PROPAGATION
BEAMS
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
LEPTON BEAMS
NOISE
PARTICLE BEAMS
RADIATIONS
RADIO NOISE
640203* - Atmospheric Physics- Magnetospheric Phenomena- (-1987)