  Spectroscopic observations made by the Extreme Ultraviolet Variability
Experiment (EVE) on board the Solar Dynamics Observatory (SDO) during the 2012
March 7 X5.4-class flare (SOL2012-03-07T00:07) are analyzed for signatures of
the non-Maxwellian kappa-distributions. Observed spectra were averaged over 1
minute to increase photon statistics in weaker lines and the pre-flare spectrum
was subtracted. Synthetic line intensities for the kappa-distributions are
calculated using the KAPPA database. We find strong departures (kappa < 2)
during the early and impulsive phases of the flare, with subsequent
thermalization of the flare plasma during the gradual phase. If the
temperatures are diagnosed from a single line ratio, the results are strongly
dependent on the value of kappa. For kappa=2, we find temperatures about a
factor of two higher than the commonly used Maxwellian ones. The non-Maxwellian
effects could also cause the temperatures diagnosed from line ratios and from
the ratio of GOES X-ray channels to be different. Multithermal analysis reveals
the plasma to be strongly multithermal at all times with flat DEMs. For lower
kappa, the DEM_kappa are shifted towards higher temperatures. The only
parameter that is nearly independent of kappa is electron density, where we
find log(N_e) $\approx$ 11.5 almost independently of time. We conclude that the
non-Maxwellian effects are important and should be taken into account when
analyzing solar flare observations, including spectroscopic and imaging ones.
