EVOLUTION OF GLOBAL RELATIVISTIC JETS: COLLIMATIONS AND EXPANSION WITH kKHI AND THE WEIBEL INSTABILITY

Nishikawa, K.; Frederiksen, Jacob Trier; Nordlund, Åke; Mizuno, Yosuke; Hardee, P.; Niemiec, J.; Gómez, J. L.; Pe’er, Asaf; Duţan, I.; Meli, A.; Sol, H.; Pohl, M.; Hartmann, D. H.

doi:10.3847/0004-637x/820/2/94

Cited by 46 publications

(85 citation statements)

References 74 publications

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“…We know that jets with different plasma compositions exhibit distinct dynamical behaviors, which will manifest as distinct morphologies in the jet evolution and its emission (Nishikawa et al 2016a(Nishikawa et al ,b, 2017(Nishikawa et al , 2019. In this letter only the case of the electron-proton plasma is discussed for both the jet and the ambient medium.…”

Section: Pic Simulation Setup Of a Jet With Helical Magnetic Field Stmentioning

confidence: 97%

Rapid particle acceleration due to recollimation shocks and turbulent magnetic fields in injected jets with helical magnetic fields

Nishikawa

Mizuno

Gómez

et al. 2020

Monthly Notices of the Royal Astronomical Society

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One of the key open questions in the study of relativistic jets is how magnetic reconnection occurs and whether it can effectively accelerate the jet's electrons. We investigate the evolution of an electronproton relativistic jet containing helical magnetic fields, focusing on the interaction with the ambient plasma. We have performed 3D particle-in-cell (PIC) simulations of a jet containing a relatively large radius with embedded helical magnetic fields, in order to examine how the helical magnetic field excites kinetic instabilities such as the Weibel instability (WI), the kinetic Kelvin-Helmholtz instability (kKHI) and the mushroom instability (MI). In our simulations these kinetic instabilities are indeed excited and particles are accelerated. We observe a recollimation-like instability near the center of the jet at the linear stage. As the electron-proton jet evolves, the helical magnetic field becomes untangled due to a reconnection-like phenomena at the end of nonlinear stage, and electrons are further accelerated by multiple magnetic reconnection events/sites within the turbulent magnetic field.

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Section: Pic Simulation Setup Of a Jet With Helical Magnetic Field Stmentioning

confidence: 97%

Rapid particle acceleration due to recollimation shocks and turbulent magnetic fields in injected jets with helical magnetic fields

Nishikawa

Mizuno

Gómez

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…Relevant instabilities are discussed in Ref. [14] and the PIC simulations demonstrate how they heat up the cloud particles. We also point out that we are studying the discontinuity between the ambient plasma and the plasma of a jet; the pair plasma has been heated in this case by internal shocks near this discontinuity.…”

Section: Simulationmentioning

confidence: 99%

Structure of a collisionless pair jet in a magnetized electron–proton plasma: flow-aligned magnetic field

Dieckmann

Folini

Hotz

et al. 2019

A&A

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Aims. We study the effect a guiding magnetic field has on the formation and structure of a pair jet that propagates through a collisionless electron–proton plasma at rest. Methods. We model with a particle-in-cell (PIC) simulation a pair cloud with a temperature of 400 keV and a mean speed of 0.9c (c - light speed). Pair particles are continuously injected at the boundary. The cloud propagates through a spatially uniform, magnetized, and cool ambient electron–proton plasma at rest. The mean velocity vector of the pair cloud is aligned with the uniform background magnetic field. The pair cloud has a lateral extent of a few ion skin depths. Results. A jet forms in time. Its outer cocoon consists of jet-accelerated ambient plasma and is separated from the inner cocoon by an electromagnetic piston with a thickness that is comparable to the local thermal gyroradius of jet particles. The inner cocoon consists of pair plasma, which lost its directed flow energy while it swept out the background magnetic field and compressed it into the electromagnetic piston. A beam of electrons and positrons moves along the jet spine at its initial speed. Its electrons are slowed down and some positrons are accelerated as they cross the head of the jet. The latter escape upstream along the magnetic field, which yields an excess of megaelectronvolt positrons ahead of the jet. A filamentation instability between positrons and protons accelerates some of the protons, which were located behind the electromagnetic piston at the time it formed, to megaelectronvolt energies. Conclusions. A microscopic pair jet in collisionless plasma has a structure that is similar to that predicted by a hydrodynamic model of relativistic astrophysical pair jets. It is a source of megaelectronvolt positrons. An electromagnetic piston acts as the contact discontinuity between the inner and outer cocoons. It would form on subsecond timescales in a plasma with a density that is comparable to that of the interstellar medium in the rest frame of the latter. A supercritical fast magnetosonic shock will form between the pristine ambient plasma and the jet-accelerated plasma on a timescale that exceeds our simulation time by an order of magnitude.

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“…They typically occur when relativistic, dilute beams propagate through background plasmas. Examples include relativistic jet propagation (Ardaneh et al 2016;Nishikawa et al 2016), gamma-ray bursts (Ramirez-Ruiz et al 2007;Ardaneh et al 2015), collisionless Shocks (Caprioli & Spitkovsky 2013;Sironi et al 2013;Stockem Novo et al 2016), black hole accretion flows (Riquelme et al 2016), and pair beams, induced by TeV-Blazars (Broderick et al 2012;Schlickeiser et al 2012Schlickeiser et al , 2013Chang et al 2014Chang et al , 2016, propagating through the intergalactic medium.…”

Section: Introductionmentioning

confidence: 99%

Importance of Resolving the Spectral Support of Beam-plasma Instabilities in Simulations

Shalaby

Broderick

Chang

et al. 2017

ApJ

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Many astrophysical plasmas are prone to beam-plasma instabilities. For relativistic and dilute beams, the spectral support of the beam-plasma instabilities is narrow, i.e., the linearly unstable modes that grow with rates comparable to the maximum growth rate occupy a narrow range of wavenumbers. This places stringent requirements on the box-sizes when simulating the evolution of the instabilities. We identify the implied lower limits on the box size imposed by the longitudinal beam plasma instability, i.e., typically the most stringent condition required to correctly capture the linear evolution of the instabilities in multidimensional simulations. We find that sizes many orders of magnitude larger than the resonant wavelength are typically required. Using one-dimensional particle-incell simulations, we show that the failure to sufficiently resolve the spectral support of the longitudinal instability yields slower growth and lower levels of saturation, potentially leading to erroneous physical conclusion.

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EVOLUTION OF GLOBAL RELATIVISTIC JETS: COLLIMATIONS AND EXPANSION WITH kKHI AND THE WEIBEL INSTABILITY

Cited by 46 publications

References 74 publications

Rapid particle acceleration due to recollimation shocks and turbulent magnetic fields in injected jets with helical magnetic fields

Rapid particle acceleration due to recollimation shocks and turbulent magnetic fields in injected jets with helical magnetic fields

Structure of a collisionless pair jet in a magnetized electron–proton plasma: flow-aligned magnetic field

Importance of Resolving the Spectral Support of Beam-plasma Instabilities in Simulations

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