Accession Number : ADA130489

Title :   Short-Wavelength Ion Waves Upstream of the Earth's Bow Shock.

Descriptive Note : Progress rept.,

Corporate Author : IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY

Personal Author(s) : Fuselier,S A ; Gurnett,D A

PDF Url : ADA130489

Report Date : 02 Jun 1983

Pagination or Media Count : 57

Abstract : The identification and explanation of short wavelength antenna interference effects observed in spacecraft plasma wave data have provided an important new method of determining limits on the wavelength, direction of propagation, and Doppler shift of short wavelength electrostatic waves. Using the ISEE-1 wideband electric field data, antenna interference effects have been identified in the ion waves upstream of the Earth's bow shock. This identification implies that wavelengths of the upstream ion waves are shorter than the antenna length. The interference effects also provide new measurements of the direction of propagation of the ion waves. The new measurements show that the wave vectors of the ion waves are not parallel to the interplanetary magnetic field (IMF) as previously reported. The direction of propagation does not appear to be controlled by the IMF. In addition, analysis of the Doppler shift of the short wavelength ion waves has provided a measurement of the dispersion relation. The upper limit on the rest frame frequency was found to be on the order of the ion plasma frequency. At this frequency, the wavelength is on the order of a few times the Debye length. The results of this study now provide strong evidence that the ion waves in the upstream region are Doppler-shifted ion acoustic waves. (Author)

Descriptors :   *Electrostatic fields, *Interference analyzers, *Spacecraft antennas, Ion beams, Wave propagation, Doppler effect, Broadband, Thermal instability, Solar wind

Subject Categories : Electrical and Electronic Equipment
      Electricity and Magnetism
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE