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Nonlinear Monte Carlo model of superdiffusive shock acceleration with magnetic field amplification
Andrei M Bykov1, Donald C Ellison2, Sergei M Osipov3
1Ioffe Institute, St. Petersburg State Polytechnical University, St. Petersburg 194021, Russia and International Space Science Institute, Bern, Switzerland.
Physical Review. E
|April 19, 2017
Summary
Collisionless shocks accelerate particles, creating a precursor region. This study models particle acceleration and magnetic field amplification in strong shocks, revealing how particle behavior drives shock structure.
Area of Science:
- Plasma physics
- Astrophysics
- Computational physics
Background:
- Collisionless shocks convert kinetic energy into hot plasma and energetic particles.
- Superthermal particles form a shock precursor, decelerating upstream flow.
- High Mach number shocks involve particle acceleration, magnetic field amplification, and particle anisotropy.
Purpose of the Study:
- To present a nonlinear Monte Carlo model for collisionless shock structure.
- To investigate the coupling between particle acceleration, magnetic field amplification, and particle transport.
- To provide a consistent description of strong shocks.
Main Methods:
- Developed a nonlinear Monte Carlo model.
- Incorporated superdiffusive (Lévy-walk) propagation of high-energy Fermi accelerated particles.
- Included particle acceleration and magnetic field amplification (MFA).
Main Results:
- The model consistently describes strong shocks.
- Superdiffusive particle transport generates quadruple anisotropy in the precursor.
- Pressure anisotropy drives a nonresonant mirror-type instability, amplifying wave modes.
Conclusions:
- The model provides a consistent description of collisionless shock structure.
- Superdiffusive particle transport is key to understanding shock precursors and particle acceleration.
- Anisotropic pressure drives instabilities that amplify magnetic fields.
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