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Asymmetry in Stimulated Emission Polarization and Irregularity Evolution During Ionospheric Electron Gyroharmonic Heating
Author(s) -
Fu H. Y.,
Scales W. A.,
Bernhardt P. A.,
Jin Y. Q.,
Briczinski S. J.
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl078957
Subject(s) - ionosphere , polarization (electrochemistry) , asymmetry , physics , plasma , ionization , electron , radar , f region , transmitter , computational physics , polarimetry , atomic physics , optics , geophysics , ion , chemistry , scattering , telecommunications , channel (broadcasting) , quantum mechanics , computer science
The first report is made of a holistic investigation of stimulated electromagnetic emission (SEE) during ionospheric electron gyroharmonic heating using a diagnostic approach at the High Frequency Active Auroral Research Program facility. The evolution of SEE polarization and plasma irregularity development near the third electron gyroharmonic 3 f ce is investigated, which provides new insights into SEE generation mechanisms by the associated parametric decay instabilities. New more complex SEE spectral line behavior is clearly observed for varying transmitter beam angles. New SEE spectral emissions are observed at ∼75 kHz when pumping below 3 f ce . The high‐frequency radar echoes and SEE polarimetry appear asymmetric for pumping above 3 f ce , which implies that the broad upshifted maximum spectral line formation involves plasma irregularities scattered by high‐frequency radar echoes. This has important implications for understanding artificial ionization layer generation during ionospheric modification.