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HF sideband generation in the ionosphere
Author(s) -
Noble S. T.,
Gordon W. E.,
Duncan L. M.,
McCoy J. E.
Publication year - 1989
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs024i003p00265
Subject(s) - sunrise , ionosphere , sideband , physics , excited state , phase (matter) , computational physics , geophysics , optics , atomic physics , quantum mechanics , microwave
The temporal development of sidebands excited near sunrise by two strong HF waves separated by a few hertz is presented. Sidebands are not observed before sunrise when the ionospheric critical frequency is less than the heater frequency. As the ionospheric density increases following sunrise and overdense conditions are established, strong sidebands emerge. Even though these results favor a mechanism which phase modulates the reflected HF wave over one which first downconverts the HF power to ULF before exciting sidebands, it is possible that either mechanism could at times contribute to sideband production.