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Solar flares are known to generate seismic waves in the Sun. We present adetailed analysis of seismic emission in sunspots accompanying M- and X-classsolar flares. For this purpose, we have used high-resolution Dopplergrams andline-of-sight magnetograms at a cadence of 45 s, along with vector magnetogramsat a cadence of 135 s obtained from Helioseismic and Magnetic Imager (HMI)instrument aboard the Solar Dynamic Observatory (SDO) space mission. In orderto identify the location of flare ribbons and hard X-ray foot-points, we havealso used H-alpha chromospheric intensity observations obtained from GlobalOscillation Network Group (GONG) instruments and hard X-ray images in 12-25 KeVband from the Reuvan Ramaty High Energy Solar Spectroscopic Imager (RHESSI)spacecraft. The Fast Fourier Transform (FFT) technique is applied to constructthe acoustic velocity power map in 2.5-4 mHz band for pre-flare, spanningflare, and post flare epochs for the identification of seismic emissionlocations in the sunspots. In the power maps, we have selected only thoselocations which are away from the flare ribbons and hard X-rays foot-points.These regions are believed to be free from any flare related artefacts in theobservational data. We have identified concentrated locations of acoustic powerenhancements in sunspots accompanying major flares. Our investigation providesevidence that abrupt changes in the magnetic fields and associated impulsivechanges in the Lorentz force could be the driving source for these seismicemissions in the sunspots during solar flares.

On the seismic emission in sunspots associated with Lorentz force changes accompanying major solar flares