Chromospheric magnetic reconnection caused by photospheric flux emergence: implications for jet-like events formation

Abstract

Magnetic reconnection in the low atmosphere, e.g. chromosphere, is investigated in various physical environments. Its implications for the origination of explosive events (small-scale jets) are discussed. A 2.5-dimensional resistive magnetohydrodynamic (MHD) model in Cartesian coordinates is used. It is found that the temperature and velocity of the outflow jets as a result of magnetic reconnection are strongly dependent on the physical environments, e.g. the magnitude of the magnetic field strength and the plasma density. If the magnetic field strength is weak and the density is high, the temperature of the jets is very low (~10<sup>4<sup/> K) as well as its velocity (~<i>40<i/> km s<sup>-1<sup/>). However, if environments with stronger magnetic field strength (40 G) and smaller density (electron density cm<sup>-3<sup/>) are considered, the outflow jets reach higher temperatures of up to K and a line-of-sight velocity of up to <i>130<i/> km s<sup>-1<sup/> which is comparable with the observational values of jet-like events.