Diagnostics of non-Maxwellian distributions in the solar corona

κ-distributions are distributions of particle energies characterized by a Maxwellian core and a high-energy tail. κ-distributions have already been observed in various structures across the solar atmosphere. We report on diagnostics of κ-distributions in observations of an active region and quiet Sun from Hinode/EIS. To avoid problems with degradation of the instrument’s sensitivity, we used spectral atlases observed shortly after the instrument’s launch. After the standard data processing procedure, we excluded missing pixels off the statistics and averaged data in selected coronal loops, moss, and off-limb quiet Sun.

Diagnostics of density, temperature, and electron distributions was performed using ratios of observed line intensities. While densities can be determined quite well, we were only capable of diagnosing a range of possible values of κ for each of the observed structures. Our results indicate that while the quiet Sun is Maxwellian, coronal loops and especially the moss show strong departures from the Maxwellian distribution.