Substorm effects on the plasma sheet on composition on March 22, 1979 (CDAW 6)

Journal Article · Fri Feb 01 04:00:00 EST 1985 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA090iA02p01243· OSTI ID:5819328

Lennartsson, W; Sharp, R D; Zwickl, R D

Data from the Plasma Composition Experiment on ISSE 1, covering the energy range 0.1--16 keV/e, show that a dramatic change took place in the plasma sheet ion composition in conjunction with the magnetic substorm activity on March 22, 1979. Beginning about 1124 UT the ion population at the ISEE 1 location changed from what appeared to be predominantly ions from the solar wind to a mixture of comparable numbers of solar wind and terrestrial ions. ISEE 1 was inbound in the predawn sector during this time, and the plasma composition experiment provided data from Rapprox. =21 R/sub E/ and LTapprox. =0130, down to Rapprox. =3 R/sub E/ and LTapprox. =0530. Prior to the substorm activity about 90--95% of the ion density was due to H/sup +/ and He/sup + +/ ions, which appeared to be mostly of solar wind origin. The H/sup +/ and He/sup + +/ components, each approximated by a Maxwell-Boltzmann distribution, had a temperature ratio T(He/sup + +/)/T(H/sup +/)approx. =4 and a density ratio n(He/sup + +/)/n(H/sup +/)approx. =1.5--3%. Both values are consistent with measurements made concurrently in the solar wind by the plasma experiment on ISSE 3. The remaining 5--10% of the density was due mainly to O/sup +/ and He/sup +/ ions of ionospheric origin. All four ion populations had broad energy spectra with mean energies of several keV/e.

• Research Organization: Lockheed Palo Alto Research Laboratory, Palo Alto, California
• OSTI ID: 5819328
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 90:A2; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHARGED PARTICLES
DISTRIBUTION FUNCTIONS
EARTH ATMOSPHERE
FUNCTIONS
HELIUM IONS
IONIC COMPOSITION
IONS
MAGNETIC BAYS
MAGNETIC STORMS
MAGNETOSPHERE
OXYGEN IONS
PLASMA DENSITY
PLASMA SHEET
PROTON DENSITY
SOLAR ACTIVITY
SOLAR WIND