A switch to reduce resistivity in smoothed particle magnetohydrodynamics

Understand

Artificial resistivity is included in Smoothed Particle Magnetohydrodynamics simulations to capture shocks and discontinuities in the magnetic field.

• Here we present a new method for adapting the strength of the applied resistivity so that shocks are captured but the dissipation of the magnetic field away from shocks is minimised.
• Our scheme utilises the gradient of the magnetic field as a shock indicator, setting {\alpha}_B = h|gradB|/|B|, such that resistivity is switched on only where strong discontinuities are present.
• The advantage to this approach is that the resistivity parameter does not depend on the absolute field strength.