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arXiv · 2202.09706

Mushroom-instability-driven Magnetic Reconnections in Collisionless Relativistic Jets

Tomohisa Kawashima·Seiji Ishiguro·Toseo Moritaka·Ritoku Horiuchi·Kohji Tomisaka
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Abstract

We study the kinetic plasma dynamics in collisionless relativistic jets with velocity shear, by carrying out particle-in-cell simulations in the transverse plane of a jet. It is discovered that intermittent magnetic reconnections (MRs) are driven by Mushroom instability (MI), which is an important kinetic-scale plasma instability in the plasma shear-flows with relativistic bulk speed. We refer to this sequence of kinetic plasma phenomena as "MI-driven MR". The MI-driven MRs intermittently occur with moving the location of the reconnection points from the vicinity of the initial velocity-shear surface towards the center of the jet. As a consequence, the number density of high energy electrons, which are accelerated by MI-driven MRs, increases with time in the region inside the initial velocity-shear surface with accompanying the generation and subsequent amplification of magnetic fields by MI. The maximum Lorentz factor of electrons increases with initial bulk Lorentz factor of the jet. A possible relation of MI-driven MR to the bright synchrotron emission in jet-spine of active galactic nucleus jets is also discussed.

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Tomohisa Kawashima, Seiji Ishiguro, Toseo Moritaka, Ritoku Horiuchi, Kohji Tomisaka. 2022-02-20. Mushroom-instability-driven Magnetic Reconnections in Collisionless Relativistic Jets. https://doi.org/10.3847/1538-4357%2Fac5591

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