Energetic He/sup +/ precipitation in a mid-latitude aurora

Journal Article · Wed Apr 01 04:00:00 EST 1987 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA092iA04p03284· OSTI ID:6836234

Ishimoto, M; Torr, M R

Optical spectra of a mid-latitude aurora on September 21--22 indicated that the observed emissions were caused by energetic ions . In an earlier paper it was shown that the spectral features could be fairly well explained by a flux of precipitating energetic O/sup +/ with characteristics similar to O/sup +/ fluxes that have been observed in large magnetic storms. A comprehensive model is used to trace the energy degradation of the incoming O/sup +/ ions, the production of energetic neutrals, and the subsequent scattering of these neutrals in altitude and energy. In this study we have computed the atmospheric impact if the incoming flux is He/sup +/ instead of O/sup +/. The results show that an energetic He/sup +/ flux is very efficient in producing both ionization and a backscattered flux out of the atmosphere. Of the total energy influx, approximately 50% goes into ionization and 40% is backscattered to the magnetosphere or escapes . By contrast the He/sup +/ flux is less efficent at heating the atmosphere <10% compared with 82%>. The He/sup +/ flux is very efficient in producing N/sub 2//sup +/ 1 N emission, but essentially does not excite the N/sub 2/ 2 P system. From these results it is concluded that the aurora observed on September 22, 1982, is well explained by an influx of energetic O/sup +/ together with a 6% admixture of He/sup +/.

• Research Organization: Applied Physics Laboratory, John Hopkins University, Laurel, Maryland
• OSTI ID: 6836234
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 92:A4; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
BACKSCATTERING
CHARGED PARTICLES
CHARGED-PARTICLE PRECIPITATION
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
HEATING
HELIUM IONS
IONIZATION
IONS
NITROGEN
NONMETALS
OXYGEN IONS
SCATTERING