Non-ideal MHD simulations of subcritical prestellar cores with non-equilibrium chemistry. (arXiv:2112.11462v1 [astro-ph.GA])

Non-ideal MHD simulations of subcritical prestellar cores with non-equilibrium chemistry. (arXiv:2112.11462v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Tritsis_A/0/1/0/all/0/1">Aris Tritsis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Federrath_C/0/1/0/all/0/1">Christoph Federrath</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Willacy_K/0/1/0/all/0/1">Karen Willacy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tassis_K/0/1/0/all/0/1">Konstantinos Tassis</a>

Non-ideal magnetohydrodynamic (MHD) effects are thought to be gravity’s
closest ally in overcoming the support of magnetic fields and in forming stars.
Here, we modify the publicly available version of the adaptive mesh refinement
code FLASH (Fryxell et al. 2000; Dubey et al. 2008) to include a detailed
treatment of non-ideal MHD and study such effects in collapsing prestellar
cores. We implement two very extended non-equilibrium chemical networks, the
largest of which is comprised of $sim$ 300 species and includes a detailed
description of deuterium chemistry. The ambipolar-diffusion, Ohmic and Hall
resistivities are then self-consistently calculated from the abundances of
charged species. We present a series of 2-dimensional axisymmetric simulations
where we vary the chemical model, cosmic-ray ionization rate, and grain
distribution. We benchmark our implementation against ideal MHD simulations and
previously-published results. We show that, at high densities
($n_{rm{H_2}}>~10^6~rm{cm^{-3}}$), the ion that carries most of the
perpendicular and parallel conductivities is not $rm{H_3^+}$ as was previously
thought, but is instead $rm{D_3^+}$.

Non-ideal magnetohydrodynamic (MHD) effects are thought to be gravity’s
closest ally in overcoming the support of magnetic fields and in forming stars.
Here, we modify the publicly available version of the adaptive mesh refinement
code FLASH (Fryxell et al. 2000; Dubey et al. 2008) to include a detailed
treatment of non-ideal MHD and study such effects in collapsing prestellar
cores. We implement two very extended non-equilibrium chemical networks, the
largest of which is comprised of $sim$ 300 species and includes a detailed
description of deuterium chemistry. The ambipolar-diffusion, Ohmic and Hall
resistivities are then self-consistently calculated from the abundances of
charged species. We present a series of 2-dimensional axisymmetric simulations
where we vary the chemical model, cosmic-ray ionization rate, and grain
distribution. We benchmark our implementation against ideal MHD simulations and
previously-published results. We show that, at high densities
($n_{rm{H_2}}>~10^6~rm{cm^{-3}}$), the ion that carries most of the
perpendicular and parallel conductivities is not $rm{H_3^+}$ as was previously
thought, but is instead $rm{D_3^+}$.

http://arxiv.org/icons/sfx.gif