Accession Number : ADA157512

Title :   Analysis and Interpretation of the Shock-Like Electrostatic Noise Observed during the AMPTE (Active Magnetospheric Particle Tracer Explorers) Solar Wind Lithium Releases.

Descriptive Note : Progress rept. for period ending Jan 85,

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

Personal Author(s) : Gurnett,D A ; Ma,T Z ; Anderson,R R ; Bauer,O H ; Haerendel,G

PDF Url : ADA157512

Report Date : May 1985

Pagination or Media Count : 51

Abstract : During the AMPTE (Active Magnetospheric Particle Tracer Explorers) solar wind lithium release on September 11, and again on September 20, 1984, an intense burst of electrostatic noise was observed near the upstream edge of the ion cloud. Comparisons with measurements by the IMP-6 and ISEE-1 spacecraft show that the spectrum and overall features of this noise are very similar to electrostatic noise observed at the earth's bow shock. A stability analysis using realistic parameters shows that the electrostatic noise can be accounted for by an ion beam-plasma instability caused by the solar wing proton beam streaming through the nearly stationary lithium cloud. The growth rate of this instability is largest when the ion density and solar wind proton density are similar, which explains why the noise only occurs near the outer edge of the ion cloud. The similarity to the noise in the earth's bow shock suggest that a shock may exist in the solar wind plasma flow upstream of the ion cloud. If the noise is associated with a shock, then it must be an electrostatic shock, since the ion cyclotron radii are too small for the existence of a MHD shock. Since the electrostatic instability occurs at phase velocities near the lithium thermal velocity, the electrostatic turbulence may play a role in heating the lithium ions and transferring momentum from the solar wind to the ion cloud.

Descriptors :   *ELECTROSTATICS, *SOLAR WIND, THERMAL PROPERTIES, VELOCITY, IONS, CLOUDS, DENSITY, STABILITY, EDGES, GROWTH(GENERAL), PLASMAS(PHYSICS), RATES, TURBULENCE, ION BEAMS, PROTONS, PHASE, LITHIUM, SHOCK, STATIONARY, RELEASE, LEADING EDGES, BOW SHOCK, EARTH(PLANET), MOMENTUM, NOISE(ELECTRICAL AND ELECTROMAGNETIC), MAGNETOSPHERE, ION DENSITY, MOMENTUM TRANSFER, PROTON BEAMS, SOLAR COSMIC RAYS

Subject Categories : Astrophysics
      Atmospheric Physics
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE