Radiative tearing - Magnetic reconnection on a fast thermal-instability time scale

Abstract

view Abstract Citations (47) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radiative tearing - Magnetic reconnection on a fast thermal-instability time scale Steinolfson, R. S. ; van Hoven, G. Abstract Two energy modification mechanisms which are known to occur in sheared magnetic fields are the tearing and thermal instabilities. These processes can be studied separately with formalisms incorporating just the effective driving mechanism of interest (finite resistivity for the tearing mode and unstable radiation for the thermal mode). A model which includes both effects, and a temperature-dependent resistivity, indicates that modified forms of these two instabilities may coexist for identical physical conditions. When they are isolated computationally, one can show that their limiting growth rates are approximately those of the uncoupled instabilities. The spatial structure and energy content of these two new hybrid processes are then individually examined and are found to differ considerably from those obtained from separate treatments of the driving mechanisms. The faster radiative instability, which has a hydromagnetically scaled growth rate like the condensation mode of the thermal instability, is shown to involve a substantial amount of magnetic field reconnection. This can be partially explained by a large temperature drop (or resistivity rise) at the X-point. The island width of the Coulomb-coupled radiative mode is 30 percent of that produced by a comparable level of the slower tearing instability. In addition, the perturbed magnetic energy in the radiative instability is 5 times that of the perturbed thermal energy, indicating an appreciable modification of the initial magnetic structure. Publication: The Astrophysical Journal Pub Date: January 1984 DOI: 10.1086/161623 Bibcode: 1984ApJ...276..391S Keywords: Magnetic Field Reconnection; Magnetohydrodynamic Stability; Solar Flares; Solar Magnetic Field; Tearing Modes (Plasmas); Thermal Instability; Lorentz Force; Resistance Heating; Reynolds Number; Solar Atmosphere; Solar Physics full text sources ADS |