Sub-oval proton aurora spots: Mapping relatively to the plasmapause
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Discipline
Earth and related Environmental sciences
Subject
Energetic protons
Equatorial planes
Formation model
Geomagnetic pulsation
Magnetospheric boundary
Plasmapause
Proton aurora
Quasi-interchange instability
Geomagnetism
Magnetosphere
Plasma diagnostics
Plasma stability
Protons
Audience
Scientific
Date
2013Metadata
Show full item recordDescription
Sub-oval proton auroras discovered by the IMAGE spacecraft correlate with EMIC waves (geomagnetic pulsations of the Pc1 range). This means that a common source of the waves and proton precipitation is the ion-cyclotron (IC) instability developing in the vicinity of the equatorial plane. Different forms of the proton auroras reflect different regimes of the IC instability and different conditions in the near-Earth equatorial magnetosphere. To understand what are the conditions for the generation of the sub-oval proton aurora one may map the aurora onto the equatorial plane and compare the projection with some important magnetospheric boundaries. In this report we compare the projection of so-called "proton aurora spots" with the location of the plasmapause. The latter is determined by the plasmapause formation model based on the quasi-interchange instability mechanism. The comparison shows that often the proton aurora spot source is located in the vicinity of the plasmapause or in the cold plasma gradient inside the plasmapause. In some events, the proton aurora spots map well outside the plasmapause. We assume that in the latter case the IC instability develops when westward drifting energetic protons interact with the cold plasma that was earlier detached from the plasmasphere.
Citation
Yahnin, A.G.; Yahnina, T.A.; Frey, H.; Pierrard, V. (2013). Sub-oval proton aurora spots: Mapping relatively to the plasmapause. , Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 99, 61-66, DOI: 10.1016/j.jastp.2012.09.018.Identifiers
scopus: 2-s2.0-84877693632
Type
Article
Peer-Review
Yes
Language
eng