EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Expansion of hot plasma with Kappa distribution in coronal flare sources

Jan Benáček1 and Marian Karlický2
Jan Benáček and Marian Karlický
  • 1Technical University of Berlin, Center for Astronomy and Astrophysics, Germany (
  • 2Astronomical Institute of the Academy of Sciences of the Czech Republic, Czech Republic

We study how hot plasma that is released during a solar flare can be confined in its source and interact with surrounding colder plasma. The X-ray emission of coronal flare sources is well explained using Kappa velocity distribution. Therefore, we compare the difference in the confinement of plasma with Kappa and Maxwellian distribution. We use a 3D Particle-in-Cell code, which is large along magnetic field lines, effectively one-dimensional, but contains all electromagnetic effects. In the case with Kappa distribution, contrary to Maxwellian distribution, we found formation of several thermal fronts associated with double-layers that suppress particle fluxes. As the Kappa distribution of electrons forms an extended tail, more electrons are not confined by the first front and cause formation of multiple fronts. A beam of electrons from the hot part is formed at each front; it generates return current, Langmuir wave density depressions, and a double layer with a higher potential step than in the Maxwellian case. We compare the Kappa and Maxwellian cases and discuss how these processes could be observed.

How to cite: Benáček, J. and Karlický, M.: Expansion of hot plasma with Kappa distribution in coronal flare sources, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11962,, 2021.