Start Date
April 2024
Location
2nd floor - Library
Abstract
Stars form when dense regions of molecular gas in our galaxy collapse due to their self-gravity. For this to occur, the magnetic field supporting these regions must diffuse out through a process known as ambipolar diffusion. We build on previous work by examining a one-dimensional self-gravitating gas with a polytropic equation of state (P∝ρε), considering cases that range from softer (ϵ<1) to stiffer (ϵ>1) than isothermal. Our results indicate that the diffusion time is not very sensitive to ϵ when stiffer than isothermal but is sensitive to ϵ when softer than isothermal. Additionally, the presence of magnetic and density fluctuations reduces the diffusion times, with the shortest diffusion times obtained for gases with large initial magnetic to gas pressure ratios and fairly soft equations of state. However, the diffusion time starts to increase significantly for ϵ ≲ 0.5, indicating that such soft equations of state are inconsistent with observations.
Ambipolar Diffusion with a Polytropic Equation of State
2nd floor - Library
Stars form when dense regions of molecular gas in our galaxy collapse due to their self-gravity. For this to occur, the magnetic field supporting these regions must diffuse out through a process known as ambipolar diffusion. We build on previous work by examining a one-dimensional self-gravitating gas with a polytropic equation of state (P∝ρε), considering cases that range from softer (ϵ<1) to stiffer (ϵ>1) than isothermal. Our results indicate that the diffusion time is not very sensitive to ϵ when stiffer than isothermal but is sensitive to ϵ when softer than isothermal. Additionally, the presence of magnetic and density fluctuations reduces the diffusion times, with the shortest diffusion times obtained for gases with large initial magnetic to gas pressure ratios and fairly soft equations of state. However, the diffusion time starts to increase significantly for ϵ ≲ 0.5, indicating that such soft equations of state are inconsistent with observations.
