Observations of transverse ion acceleration in the topside auroral ionosphere

Journal Article · Sat Feb 01 04:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA02127· OSTI ID:5361838

Garbe, G P; Arnoldy, R L ^[1]; Moore, T E ^[2]; Kintner, P M; Vago, J L ^[3]

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1. Univ. of New Hampshire, Durham (United States)
2. NASA Marshall Space Flight Center, Huntsville, AL (United States)
3. Cornell Univ., Ithaca, NY (United States)

Data obtained from a sounding rocket flight which reached an apogee of 927 km and passed through several auroral arcs are reported. During portions of the flight when the rocket was not in an energetic auroral structure, the ion data are fit to a Maxwellian function which yields the plasma parameters. Throughout the middle portion of the flight when above 700 km altitude, ion distributions having a superthermal tail were measured. These ion distributions generally coexisted with a cold thermal core distribution and peaked at pitch angles slightly greater than 90{degree}, which identifies them as conic distributions. These ions can be modeled using a bi-Maxwellian distribution function with a perpendicular (to B) temperature about 10 times greater than the parallel temperature of 0.15 eV. When the rocket was immersed in energetic auroral electron precipitation, two other ion distributions were observed. Transversely accelerated ions which represented bulk heating of the ambient population were observed. Transversely accelerated ions which represented bulk heating of the ambient population were observed continuously in these arcs. The characteristic perpendicular energy of the transversely bulk heated ions reached as high as 3 eV compared to typically less than 0.4 eV during nonauroral times. Cold ions flowing down the magnetic field were also continuously observed when the rocket was immersed in auroral electron precipitation and had downward speeds between 3 and 5 km/s. If one balances electric and collisional forces, these speeds translate to an electric field pointing into the atmosphere of magnitude 0.01 mV/m. A close correlation between auroral electron precipitation, measured electrostatic oxygen cyclotron waves, cold downflowing ions and transversely bulk heated ions will be shown.

• OSTI ID: 5361838
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A2; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
AURORAL ZONES
CHARGED PARTICLES
CHARGED-PARTICLE PRECIPITATION
CORRELATIONS
DISTRIBUTION
DISTRIBUTION FUNCTIONS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC FIELDS
ELECTRON PRECIPITATION
FUNCTIONS
ION DRIFT
ION TEMPERATURE
IONOSPHERE
IONS
PLANETARY IONOSPHERES
ROCKETS
SPATIAL DISTRIBUTION