Tearing-mediated reconnection in magnetohydrodynamic poorly ionized plasmas. II. Nonlinear evolution*

Many plasma environments, such as star-forming molecular clouds, the solar chromosphere, and the diffuse interstellar medium, are poorly ionized and threaded by dynamically important magnetic fields. Recently, we have demonstrated using a combination of analytical arguments and numerical simulations that the onset of magnetic reconnection in these poorly ionized systems is fundamentally different than what occurs in fully ionized plasmas. In this talk, we present a continuation of this work focused on the non-linear evolution of poorly ionized, tearing current sheets and their progression into steady-state reconnection. As in fully-ionized plasmas, after reconnection onsets in a current sheet, the system enters a nonlinear phase characterized by a stochastic plasmoid chain, but the characteristics of this chain differ from those of a stochastic plasmoid chain in fully ionized plasma. The reconnection rate of the system increases with the recombination rate in the plasma. In addition, the plasma in the plasmoids is characterized by an ionization fraction which is much larger than that of the background plasma. Our results could have significant implications for understanding of several important astrophysical processes, including the transport of cosmic rays in the interstellar medium.