Can the non-Maxwellian kappa-distributions be diagnosed in the solar corona?

We report on the search of signatures of the non-Maxwellian kappa-distributions in the emission line spectra of the solar corona. A survey of coronal lines is performed for single-ion and multi-ion diagnostics using ions spanning the temperature range of 0.5 - 6 MK. State-of-art excitation cross-sections are integrated directly to obtain the corresponding non-Maxwellian excitation and deexcitation rates. Ionization and recombination rates are obtained by approximative methods. We find that there are only a few good diagnostic options. This is due to majority of lines being formed from similar energy levels. The best diagnostic options rely on lines formed at different excitation tresholds, i.e., at different wavelengths. This highlights the importance of absolute intensity calibration of space-borne spectrometers. The applicability of these methods is demonstrated on analysis of a dedicated extreme-ultraviolet observations made in the Fe XI-XIII lines by the Hinode/EIS satellite during HOP 226. The observations are performed in an active region containing a filament and several coronal loops. A transient coronal loop appears at the foot of a filament and is preceded by activity within this filament. EIS spectra are used to diagnose the electron density, but also reveal that the transient loop is highly non-Maxwellian, characterized by a kappa=2 distribution. We discuss the methods for separation the non-Maxwellian effects from the effects of plasma multi-thermality arising due to finite spatial resolution, as well as the effect of kappa-distributions on the degree of multithermality diagnosed in various observed coronal features.