The Energy Conversion Rate of an Active Region Transient Brightening Estimated by Hinode Spectroscopic Observations

Abstract

Abstract We statistically estimate the conversion rate of the energy released during an active region transient brightening to Doppler motion and thermal and nonthermal energies. We used two types of data sets for the energy estimation and detection of transient brightenings. One includes spectroscopic images of Fe xiv, Fe xv, and Fe xvi lines observed by the Hinode/EUV Imaging Spectrometer. The other includes images obtained from the 211 Å channel of the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA). The observed active region was NOAA 11890 on 2013 November 9 and 10. As a result, the released Doppler motion and nonthermal energies were found to be approximately 0.1%–1% and 10%–100% of the change in the amount of thermal energy in each enhancement, respectively. Using this conversion rate, we estimated the contribution of the total energy flux of AIA transient brightenings to the active region heating to be at most 2% of the conduction and radiative losses.