D. J. Mullan and C. N. Arge
Bartol Research Institute, University of Delaware, Newark DE 19716
When reconnection occurs in partially ionized gas,
only the ions respond directly to the magnetic field: these ions attempt
to collapse towards the null line, so as to emerge as jets from the site
according to the standard picture of reconnection. Atoms participate in
the reconnection flow to the extent that they are collisionally coupled
to the ions. We have adapted the ZEUS code to model this process in a two-step
cycle: in the first step, we apply the hydrodynamic version of the ZEUS
code to the neutral fluid, and in the second step, we apply the MHD version
of ZEUS to the charged fluid. In the process of cycling back and forth
between the two fluids, momentum and energy exchange terms between the
species are included as source terms. In the emerging jets, we find that
ion/atom number ratios are enhanced over the ambient values by amounts
which depend on the degree of ionization and the plasma