Ducted whistler propagation outside the plasmapause

Journal Article · Thu Sep 01 00:00:00 EDT 1988 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA093iA09p09731· OSTI ID:5940936

Carpenter, D L ^[1]; Sulic, D M ^[2]

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1. Stanford Univ., CA (United States)
2. Geomagnetic Inst., Grocka (Yugoslavia)

A study has been made of the conditions under which lightning whistlers are observed after propagating along geomagnetic field aligned paths or ducts located outside the plasmapause. Propagation beyoun the plasmapause was found, as expected, to be rare in comparison to propagation within the nearby outer plasmasphere. However, detectable propagation beyond the plasmapause near dawn was found to occur on at least one path on roughly one half of the days studies. The path equatorial radii of propagation tended to cluster in two locations, one at the plasmapause outer edge, and the other in a belt separated from the plasmapause by a region of low activity of order 0.5 R{sub E} in extent. The outer edge of the belt was at L {approx equal} 5.5-6. The probability of whistler detection at any L value outside the plasmapause up to {approx equal} 6-7 was found to increase with local time across the dayside of the Earth; maximum activity was observed after noon. Whistler activity beyond the plasmapause was least common in the 1,800-2,400 MLT sector. Spatial variations in lightning source activity may be responsible for large variations with longitude in whistler activity outside the plasmapause and for the amny cases in which only a small fraction of whistlers within a given period exhibit evidence of plasmatrough propagation. ionospheric processes, such as wave damping, defocusing in the mid-latitude trough, scattering by 10 to 100-m irregularities, and focusing within 50 to 100-km blobs, can explain many features of the observed spatial distribution of whistler paths beyond the plasmapause and also the relatively low amplitude of the associated whistlers as compared to plasmasphere events.

• OSTI ID: 5940936
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 93:A9; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COLD PLASMA
COMPARATIVE EVALUATIONS
DAMPING
DETECTION
DISTRIBUTION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC DISCHARGES
ELECTROMAGNETIC RADIATION
EVALUATION
GEOMAGNETIC FIELD
LIGHTNING
MAGNETIC FIELDS
NOISE
PLASMA
PLASMA DENSITY
PLASMA DRIFT
PLASMAPAUSE
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
SPATIAL DISTRIBUTION
VARIATIONS
WAVE PROPAGATION
WHISTLERS