Solar Flare


Solar Flare is a phenomenon which takes place by the magnetic energy release in the solar corona. Generated thermal and bulk Kinetic energy is stored in a magnetic loop, re-distributed inside it, and the loop is cooled down. The magnetic loop contains most of its component in the high temperature and low density corona but its feet are conected to the low temperature and high density chromospheric atomosphere on the surface of the Sun. When the energy released by the flare in the corona comes over to the chromosphere, its temperature and pressure increase rapidly, and an upward flow of the high density plasma toward corona is formed by the pressure gradient created. As a result, flare loop is filled by the high density plasma and soft X-ray is emitted by its thermal bremsstrahlung. This kind of upward flow of the plasma is called as "chromospheric evaporation" and obsered as blue shifts of X-ray emission lines. Here, we will simulate energy re-distribution process in the flare loop.

Simulation Results


To show initial states, please place the mouse on figures.
Initially there are two layers; high density chromosphere and high temperature corona. Coronal region is heated by the flare and the energy released is transered to the chromosphere. As a result, upward flow of the chromospheric gas toward corona is formed.

Basic Equations

Hydrodynamic equation with thermal conduction and radiation cooling.
Here, gamma = 5/3 is the ratio of specific heat, S is cross section, g is gravity acceleration, H is static heating term, R is radiation cooling term, Hf is flare heating term, kB is Boltzmann constant, m is mean particle weight, g0 is the gravity at the photosphere (x=0), and kappa0 is a constant determined by gas property. As a heat diffusion coefficient we take Spitzer model.

Detailed Explanation

Please refer THIS document (pdf file in Japanese) as a detailed explanation.