12–23 Jul 2021
Online
Europe/Berlin timezone

Magnetic field amplification at planetary and astrophysical high Mach-number shocks

16 Jul 2021, 12:00
1h 30m
03

03

Talk CRI | Cosmic Ray Indirect Discussion

Speaker

Dr Artem Bohdan (DESY)

Description

Collisionless shocks are present everywhere in the universe, from the solar environment to distant supernovae. They are often associated with strong magnetic fields due to strong nonthermal radiation. However, it is still not well understood how magnetic fields are amplified at scales of the shock thickness. Here we use a set of large-scale Particle-In-Cell (PIC) simulations of non-relativistic perpendicular shocks in the high Mach number regime to clarify this issue. These shocks are Weibel mediated and we present evidence that the magnetic field is amplified at the shock transition due to the Weibel instability and the magnetic field strength strongly correlates with the Alfvénic Mach number. We propose a new explanation for this correlation. PIC simulation results can explain in-situ magnetic field measurements of Saturn's bow shock performed by the Cassini spacecraft.

Keywords

collisionless shocks, magnetic field, SNR, Saturn's bow shock

Subcategory Theoretical Results

Primary author

Dr Artem Bohdan (DESY)

Co-authors

Prof. Martin Pohl (DESY and Institute of Physics and Astronomy, University of Potsdam) Jacek Niemiec (Institute of Nuclear Physics Polish Academy of Sciences) Dr Paul Morris (DESY) Prof. Yosuke Matsumoto (Department of Physics, Chiba University) Prof. Takanobu Amano (Department of Earth and Planetary Science, the University of Tokyo) Prof. Masahiro Hoshino (Department of Earth and Planetary Science, the University of Tokyo) Dr Ali Sulaiman (Department of Physics and Astronomy, University of Iowa)

Presentation materials