Topic/Type: 1.1 Space & astrophysical plasmas, Poster

Formation of Balmer lines in impulsively heated solar flare atmosphere

M. Varady1, 2, J. Kasparova2, Z. Moravec1, P. Heinzel2, M. Karlicky2

1 Katedra fyziky, Univerzita J. E. Purkyně, Česk? ml?de?e 8, 400 96 ?st?nad Labem, Czech Republic
2 Astronomick? ?stav Akademie věd Česk? republiky, v.v.i., Fričova 298, 251 65 Ondřejov, Czech Republic

In the context of interpreting non-thermal hard X-ray emission emanating from the footpoints of flare loops, all contemporary flare models assign a fundamental role during the flare energy release, transport and deposition to the high energy non-thermal particle beams. In the impulsive phase of flares, the beams formed by charged particles are also guided from the acceleration site (wherever it is located) downwards along the magnetic field lines into the transition region, chromosphere and possibly photosphere. At lower atmospheric layers, due to the high density of local plasma, their kinetic energy is efficiently dissipated by Coulomb collisions, the corresponding regions are rapidly heated, and dramatic changes of temperature and ionisation occur. This results in explosive evaporation of local plasma into corona. We present modelling of optically thick hydrogen spectral lines H alpha, H beta and H gamma in early phases of solar flares evolution by the means of numerical radiative-hydrodynamics combined with a test particle approach to simulate the propagation, scattering and energy loss of an electron beam with the power-law spectrum and prescribed time dependent energy flux propagating through the solar atmosphere and depositing its energy into the solar plasma.