Stimulated Brillouin scattering during electron gyro-harmonic heating at EISCAT

Observations of secondary radiation, stimulated electromagnetic emission (SEE), produced during ionospheric modification experiments using ground-based, high-power, high-frequency (HF) radio waves are considered. The High Frequency Active Auroral Research Program (HAARP) facility is capable of gener...

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Bibliographic Details
Published in:Annales Geophysicae
Main Authors: Fu, H. Y., Scales, W. A., Bernhardt, P. A., Briczinski, S. J., Kosch, M. J., Senior, A., Rietveld, M. T., Yeoman, Timothy Kenneth, Ruohoniemi, J. M.
Format: Article in Journal/Newspaper
Language:English
Published: European Geosciences Union (EGU) 2015
Subjects:
Science & Technology
Physical Sciences
Astronomy & Astrophysics
Geosciences
Multidisciplinary
Meteorology & Atmospheric Sciences
Geology
Ionosphere
active experiments
particle acceleration
plasma waves and instabilities
ELECTROMAGNETIC EMISSION-SPECTRUM
ION GYROHARMONIC STRUCTURES
IONOSPHERIC PLASMA
PUMP FREQUENCIES
DOWNSHIFTED PEAK
HF
RADIATION
INSTABILITY
FEATURES
CUTLASS
EISCAT
Online Access:http://www.ann-geophys.net/33/983/2015/angeo-33-983-2015.html
http://hdl.handle.net/2381/35968
https://doi.org/10.5194/angeo-33-983-2015
Description
Summary:Observations of secondary radiation, stimulated electromagnetic emission (SEE), produced during ionospheric modification experiments using ground-based, high-power, high-frequency (HF) radio waves are considered. The High Frequency Active Auroral Research Program (HAARP) facility is capable of generating narrowband SEE in the form of stimulated Brillouin scatter (SBS) and stimulated ion Bernstein scatter (SIBS) in the SEE spectrum. Such narrowband SEE spectral lines have not been reported using the European Incoherent Scatter (EISCAT) heater facility before. This work reports the first EISCAT results of narrowband SEE spectra and compares them to SEE previously observed at HAARP during electron gyro-harmonic heating. An analysis of experimental SEE data shows observations of emission lines within 100 Hz of the pump frequency, interpreted as SBS, during the 2012 July EISCAT campaign. Experimental results indicate that SBS strengthens as the pump frequency approaches the third electron gyro-harmonic. Also, for different heater antenna beam angles, the CUTLASS radar backscatter induced by HF radio pumping is suppressed near electron gyro-harmonics, whereas electron temperature enhancement weakens as measured by EISCAT/UHF radar. The main features of these new narrowband EISCAT observations are generally consistent with previous SBS measurements at HAARP. Peer-reviewed Publisher Version

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