Related papers: Ambipolar Diffusion in Molecular Cloud Cores and t…
Until recently, many of the dozens of quantitative predictions of the ambipolar-diffusion theory of gravitational fragmentation (or core formation) of molecular clouds have been confirmed by observations and, just as importantly, no…
Ambipolar diffusion likely plays a pivotal role in the formation and evolution of dense cores in weakly-ionized molecular clouds. Linear analyses show that the evolutionary times and fragmentation scales are significantly greater than the…
We present the results of eighteen magnetohydrodynamical calculations of the collapse of a molecular cloud core to form a protostar. Some calculations include radiative transfer in the flux-limited diffusion approximation while others…
In the present-day universe, magnetic fields play such essential roles in star formation as angular momentum transport and outflow driving, which control circumstellar disc formation/fragmentation and also the star formation efficiency.…
We develop analytic approximations to the density evolution of prestellar cores, based on the results of hydrodynamical simulations. We use these approximations as input for a time-dependent gas-grain chemical code to investigate the…
The collapse of slowly rotating molecular cloud cores threaded by magnetic fields is investigated by high-resolution numerical simulation. Outflow formation in the collapsing cloud cores is also followed. In the models examined, the cloud…
We propose an extension of the semi-analytical solutions derived by Lin et al. (1965) describing the two-dimensional homologous collapse of a self-gravitating rotating cloud having uniform density and spheroidal shape, which includes…
We investigate the dynamical condensation process in a magnetized thermally bistable medium. We perform one-dimensional two fluid numerical simulations that describe the neutral and ionized components in the interstellar medium with purely…
Magnetic flux redistribution lies at the heart of the problem of star formation in dense cores of molecular clouds that are magnetized to a realistic level. If all of the magnetic flux of a typical core were to be dragged into the central…
We examined the gravitational contraction of isothermal molecular cloud cores with slow rotation by means of two-dimensional numerical simulations. Applying a sink-cell method, we followed the evolution of the cloud cores up to the stages…
Improving our understanding of the initial conditions and earliest stages of star formation is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. We review the properties of low-mass dense…
The chromosphere is a partially ionized layer of the solar atmosphere, the transition between the photosphere where the gas motion is determined by the gas pressure and the corona dominated by the magnetic field. We study the effect of…
Ambipolar diffusion is a process occurring in partially ionised astrophysical systems that imparts a complicated mathematical and physical nature to Ohm's law. The numerical codes that solve the magnetohydrodynamic (MHD) equations have to…
We present a parameter study of simulations of fragmentation regulated by gravity, magnetic fields, ambipolar diffusion, and nonlinear flows. The thin-sheet approximation is employed with periodic lateral boundary conditions, and the…
Ambipolar diffusion is a physical mechanism related to the drift between charged and neutral particles in a partially ionized plasma that is key in many different astrophysical systems. However, understanding its effects is challenging due…
We develop a detailed chemical model for the starless cores of strongly magnetized molecular clouds, with the ambipolar diffusion-driven dynamic evolution of the clouds coupled to the chemistry through ion abundances. We concentrate on two…
We analyze the properties of steady and time-dependent C shocks under conditions prevailing in giant molecular clouds. For steady C shocks, we show that ionization equilibrium holds and use numerical integrations to obtain the shock…
Magnetic fields play a role in the dynamics of many astrophysical processes, but they are hard to detect. In a partially ionized plasma, a magnetic field works directly on the ionized medium but not on the neutral medium, which gives rise…
The magnetic field associated with neutron stars is generally believed to be threaded inside the star. In the presence of a magnetic field, the plasma present in the interior of the star goes through several processes that lead to magnetic…
Observations indicate that dense molecular filamentary clouds are sites of star formation. The filament width determines the most unstable scale for self-gravitational fragmentation and influences the stellar mass. Therefore, constraining…