  The X-ray emission of coronal flare sources can be explained considering the
kappa electron distribution. Motivated by this fact, we study the problem of
how hot plasma with the kappa distribution of electrons is confined in these
sources. For comparison, we analyze the same problem but with the Maxwellian
distribution. We use a 3-D particle-in-cell code, which is large in one
direction and thus effectively only one-dimensional, but describing all
electromagnetic effects. In the case with the Maxwellian distribution, and in
agreement with the previous studies, we show a formation of the double layer at
the hot-cold transition region that suppresses the flux of hot electrons from
hot plasma into the cold one. In the case with the kappa distribution, contrary
to the Maxwellian case, we found that there are several fronts with the double
layers in the hot-cold transition region. It is caused by a more extended tail
in the kappa case than in the Maxwellian one. The electrons from the extended
tail freely escape from the hot plasma into a cold one. They form a beam which
generates the return current and also Langmuir turbulence, where at some
locations Langmuir waves are accumulated. At these locations owing to the
ponderomotive force, Langmuir waves generate density depressions, where the
double layers with the thermal fronts, suppressing the hot electron flux, are
formed. We also show how protons are accelerated in these processes. Finally,
we compared the kappa and Maxwellian cases and discussed how these processes
could be observed.
