Excitation of Upper-Hybrid Waves by a Thermal Parametric Instability

M. C. Lee, S. P. Kuo

Research output: Contribution to journalArticlepeer-review


A purely growing instability characterized by a four-wave interaction has been analysed in a uniform, magnetized plasma. Up-shifted and down-shifted upper-hybrid waves and a non-oscillatory mode can be excited by a pump wave of ordinary rather than extraordinary polarization in the case of ionospheric heating. The differential Ohmic heating force dominates over the ponderomotive force as the wave-wave coupling mechanism. The beating current at zero frequency produces a significant stabilizing effect on the excitation of short-scale modes by counterbalancing the destabilizing effect of the differential Ohmic heating. The effect of ionospheric inhomogeneity is estimated, showing a tendency to raise the thresholds of the instability. When applied to ionospheric heating experiments, the present theory can explain the excitation of field-aligned plasma lines and ionospheric irregularities with a continuous spectrum ranging from metre-scale to hundreds of metre-scale. Further, the proposed mechanism may become a competitive process to the parametric decay instability and be responsible for the overshoot phenomena of the plasma line enhancement at Arecibo.

Original languageEnglish (US)
Pages (from-to)463-478
Number of pages16
JournalJournal of Plasma Physics
Issue number3
StatePublished - Dec 1983

ASJC Scopus subject areas

  • Condensed Matter Physics


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