# UCL Discovery

## On the origin of 3 seismic sources in the proton-rich flare of October 28, 2003

Zharkova, VV; Zharkov, SI; On the origin of 3 seismic sources in the proton-rich flare of October 28, 2003. Astrophys.J. , 664 pp. 573-585. 10.1086/518731.

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## Abstract

The 3 seismic sources S1, S2 and S3 detected from MDI dopplergrams using the time-distance diagram technique are presented with the locations, areas and vertical and horizontal velocities of the visible wave displacements. Within the datacube of 120 Mm the horizontal velocities and the wave propagation times slightly vary from source to source. The momenta and start times measured from the TD diagrams in the sources S1-S3 are compared with those delivered to the photosphere by different kinds of high energy particles with the parameters deduced from hard X-ray and $\gamma$-ray emission as well as by the hydrodynamic shocks caused by these particles. The energetic protons (power laws combined with quasi-thermal ones, or jets) are shown to deliver momentum high enough and to form the hydrodynamic shocks deeply in a flaring atmosphere that allows them to be delivered to the photosphere through much shorter distances and times. Then the seismic waves observed in the sources S2 and S3 can be explained by the momenta produced by hydrodynamic shocks which are caused by mixed proton beams and jets occurring nearly simultaneously with the third burst of hard X-ray (HXR) and $\gamma$-ray emission in the loops with footpoints in the locations of these sources. The seismic wave in the source S1, delayed by 4 and 2 minutes from the first and second HXR bursts, respectively, is likely to be associated with a hydrodynamic shock occurring in this loop from precipitation of a very powerful and hard electron beam with higher energy cutoff mixed with quasi-thermal protons generated by either of these 2 bursts.

Type: Article On the origin of 3 seismic sources in the proton-rich flare of October 28, 2003 10.1086/518731 http://dx.doi.org/10.1086/518731 36 pages, 10 figures astro-ph, astro-ph UCL > School of BEAMS > Faculty of Maths and Physical SciencesUCL > School of BEAMS > Faculty of Maths and Physical Sciences > Space and Climate Physics http://discovery.ucl.ac.uk/id/eprint/82001