English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The X2.2-class solar flare of February 15, 2011, produced a powerful`sunquake' event, representing a seismic response to the flare impact. Theimpulsively excited seismic waves formed a compact wavepacket traveling throughthe solar interior and appeared on the surface as expanding wave ripples. TheHelioseismic and Magnetic Imager (HMI), instrument on SDO, observes variationsof intensity, magnetic field and plasma velocity (Dopplergrams) on the surfaceof Sun almost uninterruptedly with high resolution (0.5 arcsec/pixel) and highcadence (45 sec). The flare impact on the solar surface was observed in theform of compact and rapid variations of the HMI observables (Doppler velocity,line-of-sight magnetic field and continuum intensity). These variations, causedby the impact of high-energy particles in the photosphere, formed a typicaltwo-ribbon flare structure. The sunquake can be easily seen in the rawDopplergram differences without any special data processing. The source of thisquake was located near the outer boundary of a very complicated complicatedsunspot region, NOAA 1158, in a sunspot penumbra and at the penumbra boundary.This caused an interesting plasma dynamics in the impact region. I present somepreliminary results of analysis of the near-real-time data from HMI, anddiscuss properties of the sunquake and the flare impact sources.

First Sunquake of Solar Cycle 24 Observed by Solar Dynamics Observatory