EUV Diagnostics of the Kappa-Distribution in the Solar Corona Using KAPPA Package

The kappa-distributions or similar distributions with high-energy tails change individual ionization, recombination and collisional excitation rates and consequently line intensities. This allow us to diagnose non-Maxwellian distributions from spectral observations. The last version KAPPA package provides fast calculations of synthetic spectra for kappa-distributions for different kappa, temperatures, and electron densities. This enables us to study how kappa-distributions influence the observed temperature distribution in emitting plasma and to search for diagnostic opportunities. Ratios of line intensities with a big difference in the excitation energy can show marked differences with the changes of the electron distribution. We showed that mainly forbidden lines have a great potential for non-thermal diagnostics. Furthermore, spectra of the Extreme Ultraviolet Variability Experiment (EVE) on board on SDO showed that EUV solar flare spectra display signatures of the presence non-thermal distribution at least during impulsive phase. Finally, Extreme-Ultraviolet Imaging Spectrometer (EIS) onboard the Hinode spacecraft offers the Fe XI - Fe XIII lines which were employed to diagnose kappa in the active region and for the quiet Sun. It was found that the quiet Sun spectra are consistent with a Maxwellian distribution but the spectrum of coronal loops, moss, and for the transient loop observed within active region are strongly non-Maxwellian with kappa 3 or 2.