Ambipolar diffusion in smoothed particle magnetohydrodynamics

• DOI: 10.1093/mnras/stu1524
• Publication Date: 2014-08-28T02:52:49Z
• Authors: James Wurster; Daniel Price; Ben Ayliffe
• Keywords: Ambipolar diffusion; Test particle; Smoothed Particle Hydrodynamics

In partially ionised plasmas, the magnetic field can become decoupled from neutral gas and diffuse through it in a process known as ambipolar diffusion. Although diffusion has been implemented several grid codes, we here provide an implementation smoothed particle magnetohydrodynamics (SPMHD). We use strong coupling approximation which ion density is negligible, allowing single fluid approach. The equations are derived to conserve energy, positive definite contribution entropy. test both simple 1D SPMHD code fully 3D PHANTOM. wave damping yields agreement within 0.03-2 per cent of analytical result, depending on value collisional constant. oblique C-shocks results that typically agree 4 semi-analytical result. Our algorithm therefore suitable for exploring effect physical processes, such formation stars molecular clouds.