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EP: Extraterrestrische Physik

EP 15: Poster Extraterrestrische Physik

EP 15.8: Poster

Mittwoch, 22. März 2000, 16:00–16:45, Foyer

On the generation of Farley-Buneman type waves in the solar atmosphere — •C.-V. Meister², V.A. Liperovsky¹, E.V. Liperovskaya¹, K.V. Popov¹, and S.A. Senchenkov¹ — ¹Inst. Physics of the Earth Moscow — ²Astrophysical Inst. Potsdam

The possibility of the excitation of modified Farley-Buneman turbulence in the solar atmosphere is examined. It is found that the necessary conditions for the generation of the instability can be realized in the chromosphere of the sun 1000 km above the photosphere. While usual Farley-Buneman waves studied in relation to the earth’s ionosphere are almost electrostatic, the modified Farley-Buneman waves in the solar atmosphere are electromagnetic ones. It is shown that electromagnetic effects hinder the excitation of the modified waves if a parameter ξ is smaller than one. ξ is defined by the square of the ratio of ion plasma frequency times ion-neutral collision frequency to ion-cyclotron frequency times wave number times speed of light in vacuum. Under the condition ξ>1, no Farley-Buneman disturbances occur at all. In the weakly-ionized solar regions, Farley-Buneman type waves may enhance the energy dissipation of non-stationary streams of neutral gases. Besides they may vary the low-frequency acoustic noise. It seems also be possible that modified Farley-Buneman turbulence contributes to the sporadic radiation of the sun and other stars.