TY - JOUR A1 - Nishikawa, Ken-Ichi A1 - Mizuno, Yosuke A1 - Gómez, Jose L. A1 - Duţan, Ioana A1 - Meli, Athina A1 - White, Charley A1 - Niemiec, Jacek A1 - Kobzar, Oleh A1 - Pohl, Martin A1 - Pe’er, Asaf A1 - Trier Frederiksen, Jacob A1 - Nordlund, Åke A1 - Sol, Helene A1 - Hardee, Philip E. A1 - Hartmann, Dieter H. T1 - Microscopic processes in global relativistic jets containing helical magnetic fields: dependence on jet radius T2 - Galaxies N2 - In this study, we investigate the interaction of jets with their environment at a microscopic level, which is a key open question in the study of relativistic jets. Using small simulation systems during past research, we initially studied the evolution of both electron–proton and electron–positron relativistic jets containing helical magnetic fields, by focusing on their interactions with an ambient plasma. Here, using larger jet radii, we have performed simulations of global jets containing helical magnetic fields in order to examine how helical magnetic fields affect kinetic instabilities, such as the Weibel instability, the kinetic Kelvin–Helmholtz instability (kKHI) and the mushroom instability (MI). We found that the evolution of global jets strongly depends on the size of the jet radius. For example, phase bunching of jet electrons, in particular in the electron–proton jet, is mixed with a larger jet radius as a result of the more complicated structures of magnetic fields with excited kinetic instabilities. In our simulation, these kinetic instabilities led to new types of instabilities in global jets. In the electron–proton jet simulation, a modified recollimation occurred, and jet electrons were strongly perturbed. In the electron–positron jet simulation, mixed kinetic instabilities occurred early, followed by a turbulence-like structure. Simulations using much larger (and longer) systems are required in order to further thoroughly investigate the evolution of global jets containing helical magnetic fields. KW - relativistic jets KW - particle-in-cell simulations KW - global jets KW - helical magnetic fields KW - kinetic instabilities KW - kink-like instability KW - recollimation shocks KW - polarized radiation Y1 - 2017 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/51550 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-515507 N1 - © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). VL - 5 IS - (4), 58 ER -