Analysis of HMI and KONUS/WIND data shows that photospheric and helioseismic flare impacts started to develop in compact regions in close vicinity of the magnetic polarity inversion line in the pre-impulsive phase before detection of hard X-ray emission.
Waves of magnetic-field variations were observed associated with the sunquake waves that were excited by the X9.3 flare on 2017 September 6. The nature and cause of the magnetic waves are discussed after the phase relations and power distributions of the magnetic waves and Doppler-observed sunquake waves are investigated.
An X9.3 flare excited strong yet unusual sunquakes.
New HMI high-cadence vector magnetograms are now available. Observations every 135 or 90 seconds reveal the rapid magnetic evolution occurring during major solar eruptions.