Nanoflash Distribution at the Solar Minimum

Abstract

We use data from the Atmospheric Imaging Assembly (AIA) telescope on the Solar DynamicsObservatory (SDO) spacecraft in the 171 Å channel to investigate the spatial distribution of low-energyflares (nanoflashes). We have studied two periods: 05/20/2019 from 1200 UT to 1300 UT and 05/10/2020from 1200 UT to 1300 UT. In total, we found 87974 nanoflares with an average formation rate of 6.0 ×10‒21 cm–2 s–1. For solar latitudes from 0° up to 50° the nanoflare formation rate is approximately uniformwith a standard deviation of about 25%. We have found an asymmetry in the rate of formation of nanoflaresin the southern and northern hemispheres of the Sun: the rate of formation of nanoflares in the southernhemisphere was 34–42% higher than in the northern one. During this period, the same asymmetry wasalso observed for ordinary f lares. We also found a weak dependence of the nanof lare formation rate on thesolar cycle: the number of nanof lares increases with higher solar activity.