Heating of coronal loops by fast mode MHD waves |
| |
Authors: | Shadia Rifai Habbal Egil Leer Thomas E Holzer |
| |
Institution: | (1) High Altitude Observatory, National Center for Atmospheric Research, 80307 Boulder, Colo., U.S.A.;(2) Present address: Center for Astrophysics, 02138 Cambridge, Mass., U.S.A.;(3) Present address: University of Tromsø, The Auroral Observatory, Tromsø, Norway |
| |
Abstract: | A possible mechanism for the formation and heating of coronal loops through the propagation and damping of fast mode waves is proposed and studied in detail. Loop-like field structures are represented by a dipole field with the point dipole at a given distance below the solar surface. The density of the medium is determined by hydrostatic equilibrium along the field lines in an isothermal atmosphere. The fast mode waves propagating outward from the coronal base are refracted into regions with a low Alfvén speed and suffer collisionless damping when the gas pressure becomes comparable to the magnetic pressure. The propagation and damping of these waves are studied for three different cases: a uniform density at the coronal base, a density depletion within a given flux tube, and a density enhancement within a given flux tube. The fast mode waves are found to be important in the formation and heating of the loops if the wave energy flux density is of the order 105 ergs cm-2 s-1 at the coronal base.The National Center for Atmospheric Research is sponsored by the National Science Foundation. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|