TY  - JOUR
A1  - Nishikawa, Ken-Ichi
A1  - Frederiksen, J. T.
A1  - Nordlund, A.
A1  - Mizuno, Y.
A1  - Hardee, P. E.
A1  - Niemiec, J.
A1  - Gomez, J. L.
A1  - Dutan, I.
A1  - Meli, A.
A1  - Sol, H.
A1  - Pohl, Martin
A1  - Hartmann, D. H.
T1  - EVOLUTION OF GLOBAL RELATIVISTIC JETS: COLLIMATIONS AND EXPANSION WITH
kKHI AND THE WEIBEL INSTABILITY
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - In the study of relativistic jets one of the key open questions is their interaction with the environment. Here. we study the initial evolution of both electron-proton (e(-) - p(+)) and electron-positron (e(+/-)) relativistic jets, focusing on their lateral interaction with ambient plasma. We follow the evolution of toroidal magnetic fields generated by both the kinetic Kelvin-Helmholtz and Mushroom instabilities. For an e(-) - p(+) jet, the induced magnetic field collimates the jet and electrons are perpendicularly accelerated. As the instabilities saturate and subsequently weaken, the magnetic polarity switches from clockwise to counterclockwise in the middle of the jet. For an e(+/-) jet, we find strong mixing of electrons and positrons with the ambient plasma, resulting in the creation of a bow shock. The merging of current filaments generates density inhomogeneities that. initiate a forward shock. Strong jet-ambient plasma mixing prevents a full development of the jet (on the scale studied), revealing evidence for both jet collimation and particle acceleration in the forming bow shock. Differences in the magnetic field structure generated by e(-) - p(+) and e(+/-) jets may contribute to the polarization properties of the observed emission in AGN jets and gamma-ray bursts.
KW  - acceleration of particles
KW  - plasmas
KW  - radiation mechanisms: non-thermal
KW  - relativistic processes
KW  - stars: jets
KW  - Sun: magnetic fields
Y1  - 2016
U6  - https://doi.org/10.3847/0004-637X/820/2/94
SN  - 0004-637X
SN  - 1538-4357
VL  - 820
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -