Robustness of the filamentation instability as shock mediator in arbitrarily oriented magnetic field

Abstract

The filamentation instability (sometimes also referred to as "Weibel") is a key process in many astrophysical scenario. In the Fireball model for Gamma Ray Bursts, this instability is believed to mediate collisionless shock formation from the collision of two plasma shells. It has been known for long that a flow aligned magnetic field can completely cancel this instability. We show here that in the general case where there is an angle between the field and the flow, the filamentation instability can never be stabilized, regardless of the field strength. The presented model analyzes the stability of two symmetric counter-streaming cold electron/proton plasma shells. Relativistic effects are accounted for, and various exact analytical results are derived. This result guarantees the occurrence of the instability in realistic settings fulfilling the cold approximation.

To appear in Physics of Plasmas Letters

References in corpus (7)

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Cited by in corpus (4)

• Hierarchy of instabilities for two counter-streaming magnetized pair beams: influence of field obliquity
• Robustness of the filamentation instability in arbitrarily oriented magnetic field: Full 3D calculation
• Robustness of the filamentation instability for asymmetric plasma shells collision in arbitrarily oriented magnetic field
• Compton driven beam formation and magnetisation via plasma microinstabilities