Accession Number : ADA193022

Title :   Field-Aligned Structure of the Storm Time Pc 5 Wave of November 14-15, 1979,

Corporate Author : AEROSPACE CORP EL SEGUNDO CA SPACE SCIENCES LAB

Personal Author(s) : Takahashi, K ; Higbie, P R ; Fennell, J F ; Amata, E

PDF Url : ADA193022

Report Date : 01 Feb 1988

Pagination or Media Count : 42

Abstract : Magnetic field data from the four satellites--SCATHA (P78-2), GOES 2, GOES 3, and GEOS 2--have been analyzed to examine the magnetic-field-aligned structure of a storm time Pc 5 wave which occurred on November 14-15, 1979. The wave had both transverse and compressional components. At a given instance, the compressional and the radial components oscillated in phase or 180 deg out of phase, and the compressional and the azimuthal components oscillated +90 deg or -90 deg out of phase. In addition, each component changed its amplitude with magnetic latitude: the compressional component had a minimum at the magnetic equator, whereas the transverse components had a maximum at the equator and minima several degrees off the equator. At 180 deg relative phase switching among the components occurred across the latitudes of amplitude minima. From these observations, the field-line displacement of the wave is confirmed to have an antisymmetric standing structure about the magnetic equator with a parallel wave length of a few earth radii. We aslo observed other intriguing properties of the wave, such as different parallel wavelengths of different field components and small-amplitude second harmonics near the nodes. A dielectric tensor appropriate for the ring current plasma is found to give an explanation for the relation between the polarization and the propagation of the wave. However, plasma data available from SCATHA do not support either the drift-mirror instability of Hasegawa or the coupling between a drift-mirror wave and a shear wave Alfven wave, as discussed by Walker and coworkers. Keywords: Magnetic pulsations; Magnetosphere; Standing waves.

Descriptors :   *GEOMAGNETISM, *MAGNETIC STORMS, *MAGNETOSPHERE, ALIGNMENT, AMPLITUDE, AZIMUTH, DIELECTRICS, EARTH(PLANET), ELECTROMAGNETIC FIELDS, EQUATORIAL REGIONS, LATITUDE, MAGNETIC FIELDS, MAGNETOSPHERE, PARALLEL ORIENTATION, PLASMAS(PHYSICS), POLARIZATION, PROPAGATION, PULSES, RADIUS(MEASURE), RINGS, STANDING WAVES, STORMS, TENSORS, TRANSVERSE, MAGNETOMETERS, SCIENTIFIC SATELLITES

Subject Categories : Atmospheric Physics
      Geomagnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE