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First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics

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journal contribution
posted on 24.10.2012, 08:55 by F. Honary, T. R. Robinson, D. M. Wright, A. J. Stocker, M. T. Rietveld, I. McCrea
It is well known that the ionospheric plasma response to high-power HF radio waves changes drastically as the heater frequency approaches harmonics of the electron gyrofrequency. These include changes in the spectrum of the stimulated electromagnetic emission, reduction in the anomalous absorption of low-power diagnostic waves propagating through the heated volume, and reduction in the large scale F-region heating. Theoretical models as well as previous experimental evidence point towards the absence of small-scale field-aligned plasma density irregularities at pump frequencies close to electron gyroharmonics as the main cause of these changes. Results presented in this paper are the first direct observations of the reduced striations at the 3rd gyroharmonic made by the CUTLASS radar. In addition, simultaneous EISCAT observations have revealed that the "enhanced ion-line" usually present in the EISCAT ion-line spectrum during the first few seconds after heater switch on, persisted at varying strengths while the heater was transmitting at frequencies close to the 3rd electron gyroharmonics.

History

Citation

ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES, 1999, 17 (9), pp. 1235-1238

Published in

ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES

Publisher

Springer Verlag

issn

0992-7689

Copyright date

1999

Available date

24/10/2012

Publisher version

http://www.ann-geophys.net/17/1235/1999/angeo-17-1235-1999.html

Language

English