The role of ring current O sup + in the formation of stable auroral red arcs

Journal Article · Wed Jul 01 00:00:00 EDT 1987 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA092iA07p07487· OSTI ID:5595720

Kozyra, J U; Cravens, T E; Nagy, A F ^[1]; Shelley, E G ^[2]; Comfort, R H ^[3]; Brace, L H ^[4]

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1. Univ. of Michigan, Ann Arbor (United States)
2. Lockheed Missiles and Space Company, Inc., Palo Alto, CA (United States)
3. Univ. of Alabama, Huntsville (United States)
4. NASA Goddard Space Flight Center, Greenbelt, MD (United States)

Coulomb collisions between ring current protons and thermal electrons were first proposed by Cole (1965) as the energy source for stable auroral red (SAR) arcs. Recent observations have shown that the ring current and magnetospheric plasma contain significant amounts of heavy ions (Johnson et al., 1977; Young et al., 1977; Geiss et al., 1978; and others). In fact, the ring current is often dominated by heavy ions at those energies (E {le} 17 keV) important for Coulomb collisions on SAR arc field lines (Kozyra et al., 1986a). Observations (during four SAR arcs in 1981) of thermal and energetic ion populations by the Dynamics Explorer 1 satellite in the magnetospheric energy source region and nearly simultaneous Langmuir probe measurements of enhanced electron temperatures by Dynamics Explorer 2 within the SAR arc at F region heights have allowed the authors to examine the role of heavy ions in the formation of SAR arcs. They find that (1) sufficient energy is transferred to the electron gas at high altitudes via Coulomb collisions between the observed ring current ions and thermal electrons to support the enhanced (SAR arc) F region electron temperatures measured on these field lines, (2) the latitudinal variation in the electron heating rates calculated using observed ion populations is consistent with the observed variation in electron temperature across the SAR arc, and (3) in all cases, ring current O{sup +} is the major source of energy for the SAR arcs. This implies a relationship between the heavy ion content of the magnetospheric plasma and the occurrence frequency and intensity of SAR arcs.

• OSTI ID: 5595720
• Journal Information: Journal of Geophysical Research; (United States), Vol. 92:A7; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
EARTH MAGNETOSPHERE
IONIC COMPOSITION
COLLISIONS
ELECTRON TEMPERATURE
ELECTRONS
ENERGY SOURCES
ENERGY TRANSFER
EXPLORER SATELLITES
HEAVY IONS
IONOSPHERE
LATITUDE EFFECT
OXYGEN IONS
PROTONS
RING CURRENTS
BARYONS
CHARGED PARTICLES
CURRENTS
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELEMENTARY PARTICLES
FERMIONS
GEOGRAPHICAL VARIATIONS
HADRONS
IONS
LEPTONS
NUCLEONS
PLANETARY IONOSPHERES
SATELLITES
VARIATIONS
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)