On the threshold electric field for the @1-m auroral irregularity appearance

Journal Article · Fri Sep 01 04:00:00 EDT 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA09p12043· OSTI ID:6048143

Kustov, A; Uspensky, M ^[1]; Kangas, J; Huuskonen, A ^[2]; Nielsen, E ^[3]

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1. Polar Geophysical Institute, Murmansk (USSR)
2. Univ. of Oulu (Finland)
3. Max-Planck-Institut fuer Aeronomie, Katlenburg-Lindau (West Germany)

The authors study the electric field threshold for 1-m auroral electrojet irregularity excitation, using data from the special Finnish EISCAT experiment held on November 17, 1983. They found that at times irregularities can arise when the ionospheric electric field is 5-15 mV/m, i.e., well below the Farley-Buneman instability threshold. The electron density fluctuations derived here are increased when the E field becomes more than 15 mV/m. As a result the dependence of electron density fluctuation amplitude on electric fields has a kind of a soft E field threshold. Possible reasons for such a dependence are discussed. They show that unresolved ionospheric microstructure in the radar scattering volume can cause this threshold spreading.

• OSTI ID: 6048143
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 94:A9; ISSN 0148-0227; 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
CURRENTS
DATA ANALYSIS
DRIFT INSTABILITY
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTROJETS
ELECTRON DENSITY
FLUCTUATIONS
INSTABILITY
IONOSPHERE
MEASURING INSTRUMENTS
MORPHOLOGY
PLANETARY IONOSPHERES
PLASMA DRIFT
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
RADAR
RANGE FINDERS
VARIATIONS