Prediction of Dn Resonances in the Solar Corona

V.A. Osherovich, J. Fainberg, R.F. Benson, R. MacDowall


A new plasma wave mode has been proposed with quantized frequencies 
fDn = 3/pi (fpefce)^1/2 n^1/2, n=1,2,... where fpe is the electron plasma
frequency and fce is the electron gyrofrequency. These frequencies have been
associated with a spectrum of emissions known as the Dn resonance stimulated by
ionospheric topside sounders [Osherovich, 1987]. The foundations and 
observational support for this new electromagnetic mode have been summarized in
the recent review by Osherovich et al. [2005] for three plasmas: the Earths
ionosphere (topside radio sounding from Alouette 2, ISIS 1 and ISIS 2
satellites), the Earth's magnetosphere (radio sounding from the IMAGE
spacecraft) and in Jupiter's Io plasma torus (radio sounding from the Ulysses
space probe). For these plasmas, the electron densities, magnetic fields and
electron temperatures are quite different but in each of these plasmas there
exists extended regions where the range of is roughly the same, namely 1 <+
fpe/fce <= 8. From available observations of the solar corona and coronal loops,
we conclude that the two-million degree corona is the fourth example of a
magnetized plasma containing extended regions with the same range. Therefore we
predict the presence of Dn resonances with their distinctive square root of n
frequency spectrum in the solar corona.

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Spring Joint Assembly, American Geophysical Union, Baltimore, Maryland, U.S.A., 
23-26 May 2006