Investigating small scale particle acceleration events at the sun and its implications for coronal heating

Abstract

Particle acceleration in the Solar atmosphere is an ill understood problem This lack ofunderstanding creates impediments in our knowledge about how energy is generated andtransported in the solar atmosphere Studies show that the majority of energy released in transient events are used in the acceleration of particles A proper understanding of this process is then vital to understand how the solar corona is heated Since most of the coronal heating is carried out by small transient events in this thesis we lay particular emphasis on understanding the particle acceleration dynamics in them With the current sensitivity levels of space instruments it is challenging to directly observe andquantify extremely small energy release events on the scale of nanoflares Hence we turned our attention on very small flaring events which had both HXR and a SEP correspondence but which did not have any big flares or CMEs associated with it The simultaneous occurrence of HXR radiation and SEP particles makes sure that the selected events for the study had significant amounts of particle acceleration From our study we found that these small events accelerations almost similar amounts of electrons at the HXR producing electrons and SEP electrons This number for bigger events are much smaller i e the number of SEP electrons that escape towards Earth as SEP is only a small fraction of the HXR producing electron We observe that the ratio of the number of escaping electrons to that of HXR electrons ranges from 6 to over 100 By comparison this ratio is only 8764 0 2 for large flares The total energy in the HXR producing electrons is 8764 10 8203 24 8211 10 8203 26 while the same for electron population that escaped into the interplanetary medium is 8764 10 8203 23 8203 to 10 8203 25 8203 erg James et al 2017 In another study we used high temporal resolution type I noise storm data from the NRH toinvestigate the energetics Type I noise storm bursts represents some of the smallest examples of newline newline