On the sources of energization of molecular ions at ionospheric altitudes

Journal Article · Thu Dec 01 04:00:00 EST 1994 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/94JA01738· OSTI ID:85456

Peterson, W K; Abe, T; Fukunishi, H; Greffen, M J; Hayakawa, H; Kasahara, Y; Kimura, I; Matsuoka, A; Mukai, T; Nagatsuma, T ^[1]

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1. National Research Council of Canada, Ottawa (Canada)

During geomagnetically active times, the suprathermal mass spectrometer on the Akebono satellite frequency observes upflowing molecular ions (NO(+), N2(+), O2(+)) in the 2-3 Earth radii geocentric distance regions in the auroral zone. Molecular ions originating at ionospheric altitudes must acquire an energy of the order of 10 eV in order to overcome gravitation and reach altitudes greater than 2 R(sub E). This energy must be acquired in a time short compared with the local dissociative recombination lifetime of the ions; the latter is of the order of minutes in the F region ionosphere (300-500 km altitude). Upflowing molecular ions thus provide a test particle probe into the mechanisms responsible for heavy ion escape from the ionosphere. In this paper we analyze the extensive complement of plasma, field, and wave data obtained on the Akebono satellite in a number of upflowing molecular ion events observed at high altitudes (5000-10,000 km). We use these data to investigate the source of energization of the molecular ions at ionospheric altitudes. We show that Joule heating and ion resonance heating do not transfer enough energy or do not transfer it fast enough to account for the observed fluxes of upflowing molecular ions. We found that the observed field-aligned currents were too weak to support large-scale field-aligned current instabilities at ionospheric altitudes.

• Sponsoring Organization: USDOE
• OSTI ID: 85456
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: A12 Vol. 99; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
IONOSPHERE
MAGNETOHYDRODYNAMICS
MASS SPECTROMETERS
REMOTE SENSING