Parametric instability producing broad symmetrical structure in the spectrum of ionospheric heating-induced radiation

S. P. Kuo

Research output: Contribution to journalArticle


A four-wave interaction process in which an O-mode electromagnetic pump decays parametrically into a lower hybrid decay mode and two-electron Bernstein sidebands is analyzed. It is shown that the instability can be excited in a spatial region near the electron Bernstein/upper hybrid double resonance and in a narrow pump frequency range slightly below the third harmonic electron cyclotron resonance. The two electron Bernstein sidebands have about the same intensity and thus, produce Broad Symmetrical Structure (BSS) in the emission spectrum after being converted into electromagnetic radiation by scattering off background field-aligned density irregularities. The results also show that the size of the instability zone becomes very small as the pump frequency operates near a cyclotron harmonic higher than the third. Thus, the converted emission will be too weak to be detected. This explains why the BSS feature in the spectrum of stimulated electromagnetic emissions (SEEs) has only been observed in the third harmonic case.

Original languageEnglish (US)
Pages (from-to)3194-3199
Number of pages6
JournalPhysics of Plasmas
Issue number9
StatePublished - Sep 1997


ASJC Scopus subject areas

  • Condensed Matter Physics

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