Description
(Text)
The goal of this thesis work was the investigation of the physical processes involved in evolution of solar coronal Bright Points (BPs) by means of a three-dimensional magnetohydrodynamic (MHD) numerical simulation. We investigated the energy budget with emphasis on the relative role and contribution of adiabatic compression versus current dissipation to the formation of coronal BPs. We used a three-dimensional resistive MHD model, initialized with an extrapolation of the observed magnetic field from SOHO/MDI magnetograms. We showed quantitatively the small role of Joule heating in BP formation and concluded that it cannot be considered a viable process unless the diffusion regions have a much larger volume filling factor than currently thought. The results also indicate that compression is an important processes in the energy budget. After this we concentrated on radiative losses in optically thin plasmas and heat conduction in the model.
(Extract)
There are two main categories of theoretical models of the extra ordinary strong coronal heating trying to explain the very high temperature of the outer atmosphere by orders of magnitude than the solar surface temperature. In both classes of models energy is transported from below the surface via the photospheric motions of the magnetic fields footpoints into the corona. Classification of the relevant models are according to the way the photospheric driver and the corona are coupled or, more precisely, according to the timescales of the electromagnetical response of the corona to the photospheric driver.
