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

¹ Armagh Observatory, College Hill, Armagh BT61 9DG, N. Ireland e-mail: jyd@arm.ac.uk
² School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, PR China

Received: 10 August 2009
Accepted: 17 December 2009

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 (~10⁴ K) as well as its velocity (~40 km s^-1). However, if environments with stronger magnetic field strength (40 G) and smaller density (electron density  cm^-3) are considered, the outflow jets reach higher temperatures of up to  K and a line-of-sight velocity of up to 130 km s^-1 which is comparable with the observational values of jet-like events.