Mirror instability and the origin of morningside auroral structure

Journal Article · Sun May 01 04:00:00 EDT 1983 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA088iA05p04041· OSTI ID:5846666

Chiu, Y T; Schulz, M; Fennell, J F; Kishi, A M

Auroral optical imagery shows marked differences between auroral features of the evening and morning sectors: The separation between diffuse and discrete auroras in the evening sector is not distinct in the morning sector, which is dominated by auroral patches and multiple banded structures aligned along some direction. Plasma distribution function signatures also show marked differences: downward electron beams and inverted-V signatures prefer the evening sector, while the electron spectra on the morning sector are similar to the diffuse aurora. We have constructed a theory of morningside auroras consistent with these features. The theory is based on modulation of the growth rates of electron cyclotron waves by the mirror instability, which is in turn driven by inward-convected ions that have become anisotropic. This modulation produces alternating bands of enhanced and reduced electron precipitation which approximate the observed multiple auroral bands and patches of the morning sector.

• Research Organization: Space Sciences Laboratory, The Aerospace Corporation, El Segundo, California 90245
• OSTI ID: 5846666
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 88:A5; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
CHARGED-PARTICLE PRECIPITATION
DAILY VARIATIONS
ELECTRON PLASMA WAVES
ELECTRON PRECIPITATION
INSTABILITY
INSTABILITY GROWTH RATES
PLASMA DENSITY
PLASMA INSTABILITY
PLASMA WAVES
VARIATIONS