Effect of thermal conduction and radiation on the dynamics of a flaring coronal loop

Abstract

A systematic study of the effects of thermal conduction and radiation (Cox-Tucker type) on the dynamic response of a coronal loop is presented. The study is based on a one-fluid hydrodynamic description of a magnetic flux loop subject to a sudden localized heating, simulating the flare energy release. Numerical results are obtained for the heating of a full loop at one end and symmetrical heating at both ends. The results show that: (1) The basic response is the propagation of a hydrodynamic shock; (2) thermal conduction (Coulomb type) has significant effects; and (3) radiation has only minor influence unless the density exceeds 1011 cm−3. It is noted that the uniform flaring of a loop is associated with heating of long duration. Short pulse-like heating results in the nonuniform brightening and propagation of luminous fronts similar to that sometimes observed in flare loops.