Seismic Images of a Solar Flare

We have used helioseismic holography to render seismic images of the solar flare of 1996 July 9, whose helioseismic signature was recently reported by Kosovichev & Zharkova. We computed time series of "egression power maps" in 2 mHz bands centered at 3.5 and 6 mHz. These images suggest an oblong acoustic source associated with the flare some 18 Mm in the north-south direction and approximately 15 Mm in the east-west direction. The considerable preponderance of the flare acoustic power emanates in the 3.5 mHz band. However, because the ambient noise in the 6 mHz band is much lower and the diffraction limit for 6 mHz waves is much finer, the flare is rendered far more clearly in the 6 mHz band. The 6 mHz flare signature lags the 3.5 mHz by approximately 4 minutes.

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