Altitude Dependence of Auroral Beam Generated Electrostatic Noise

  1. S.-I. Akasofu and
  2. J.R. Kan
  1. J. E. Maggs

Published Online: 26 MAR 2013

DOI: 10.1029/GM025p0428

Physics of Auroral Arc Formation

Physics of Auroral Arc Formation

How to Cite

Maggs, J. E. (1981) Altitude Dependence of Auroral Beam Generated Electrostatic Noise, in Physics of Auroral Arc Formation (eds S.-I. Akasofu and J.R. Kan), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM025p0428

Author Information

  1. Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90024

Publication History

  1. Published Online: 26 MAR 2013
  2. Published Print: 1 JAN 1981

ISBN Information

Print ISBN: 9780875900506

Online ISBN: 9781118664360

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Keywords:

  • Auroras—Addresses, essays, lectures

Summary

A specific altitude dependent model of the auroral beam is used to investigate the effects of changing ionospheric parameters on the power flux spectrum of beam generated electrostatic noise. In the model the beam pitch angle distribution evolves conserving the first adiabatic (flux) invariant. The beam generates electrostatic whistler noise through Landau resonance over most of the field line. Cyclotron resonances can drive narrow band upper hybrid noise at low altitudes. Only a relatively narrow range of beam source densities generates noise linearly along the entire field line. Generally at altitudes of a few thousand kilometers the beam generated whistler noise is intense enough that nonlinear plasma processes can be expected to be important. The evolution of the beam in the presence of this intense electrostatic noise is not investigated using this model.