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Title:
Power Fluctuations in Meteor Head Echoes Observed with the EISCAT VHF Radar
Authors:
Kero, J.; Szasz, C.; Pellinen-Wannberg, A.; Wannberg, G.; Westman, A.
Affiliation:
AA(Swedish Institute of Space Physics, P.O. Box 812, Kiruna, SE-981 28 Sweden ; ), AB(Swedish Institute of Space Physics, P.O. Box 812, Kiruna, SE-981 28 Sweden ; ), AC(Swedish Institute of Space Physics, P.O. Box 812, Kiruna, SE-981 28 Sweden ; ), AD(EISCAT Scientific Association, P.O. Box 164, Kiruna, SE-981 23 Sweden ; ), AE(EISCAT Scientific Association, P.O. Box 164, Kiruna, SE-981 23 Sweden ; )
Publication:
American Geophysical Union, Fall Meeting 2004, abstract #SH51D-0295
Publication Date:
12/2004
Origin:
AGU
AGU Keywords:
6015 Dust, 6213 Dust, 6245 Meteors, 6999 General or miscellaneous, 2129 Interplanetary dust
Bibliographic Code:
2004AGUFMSH51D0295K

Abstract

Meteor head echoes are radio wave reflections from the plasma generated by the interaction of meteoroids with the atmosphere at about 80-120 km altitude. The echoes are characterized by being transient and Doppler shifted. The received power is confined in range, as from a point source, and it moves with the line-of-sight velocity of the meteoroid. Head echoes arise and disappear as meteoroids pass through the radar beam, and usually last from one tenth to a few tenths of a second. Some meteor echoes in the data from a meteor experiment carried out with the EISCAT VHF radar at 224 MHz contain peculiar pulsations in received power. These pulsations are in the frequency range 50-100 Hz. The interpulse period of the experiment was 2.167 ms, i.e., meteoroid line-of-sight velocity and echo power was monitored at 461 Hz. This limits the observable power fluctuation frequency range to about 10-230 Hz. The process causing the echo power pulsations is at present not identified. Plasma effects are the most likely cause, a presumable mechanism is for instance asymmetrical dust grains in rotation causing a modulation of the ionization rate.
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