Magnetic Field Amplification by the Weibel Instability at Planetary and Astrophysical Shocks with High Mach Number

Collisionless shocks are ubiquitous in the Universe and often associated with a strong magnetic field. Here, we use large-scale particle-in-cell simulations of nonrelativistic perpendicular shocks in the high-Mach-number regime to study the amplification of the magnetic field within shocks. The magnetic field is amplified at the shock transition due to the ion-ion two-streamWeibel instability. The normalized magnetic field strength strongly correlates with the Alfvenic Mach number. Mock spacecraft measurements derived from particle-in-cell simulations are fully consistent with those taken in situ at Saturn's bow shock by the Cassini spacecraft.

Automated summary

The study investigates the amplification of magnetic field within nonrelativistic perpendicular shocks through large-scale particle-in-cell simulations. It is found that the magnetic field is amplified at the shock transition due to ion-ion two-stream Weibel instability and strongly correlates with the Alfvenic Mach number. Measurements derived from particle-in-cell simulations are consistent with those taken at Saturn's bow shock by the Cassini spacecraft.