DYNAMICS OF THE PHYSICAL STATE DURING 2-CURRENT-LOOP COLLISIONS

A model of two-current-loop collisions is presented to explain the imp ulsive nature of solar flares. From MHD equations considering the grav ity and resistivity effects we find self-consistent expressions and a set of equations governing the behavior of all physical quantities jus t after magnetic reconnection has taken place. Numerical simulations h ave revealed that the most important parameters of the problem are the plasma beta and the ratio of initial values of pressure gradient in t he longitudinal and radial directions. Thus, the low plasma beta case during a Y-type interaction (initial longitudinal pressure gradient is comparable with initial radial pressure gradient) shows a rapid pinch and simultaneous enhancement of all physical quantities, including th e electric field components, which are important for high-energy parti cle acceleration. However, an increase of the plasma beta causes a wea kening of the pinch effect and a decrease of extreme values of all phy sical quantities. On the other hand, for an X-type collision (initial longitudinal pressure gradient is much greater than initial radial pre ssure gradient), which is able to provide a jet, the increase of the p lasma beta causes a high velocity jet. As for a I-type collision (init ial longitudinal pressure gradient is much less than initial radial pr essure gradient) it shows neither jet production nor very strong enhan cement of physical quantities. We also consider direct and oblique col lisions, taking into account both cases of partial and complete reconn ection.