scholarly journals Relativistic Jet Simulations of the Weibel Instability in the Slab Model to Cylindrical Jets with Helical Magnetic Fields

2018 ◽  
Author(s):  
Kenichi Nishikawa ◽  
Yosuke Mizuno ◽  
Jose L. Gomez ◽  
Ioana Dutan ◽  
Athina Meli ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Relativistic Jets ◽  
Astrophysical Plasmas ◽  
Weibel Instability ◽  
Particle In Cell ◽  
Relativistic Shocks ◽  
Relativistic Jet ◽  
The Us ◽  
Solar Plasmas ◽  
Pic Method

The Particle-In-Cell (PIC) method has been developed in order to investigate microscopic phenomena, and with the advances of computing power, newly developed codes have been used for several fields such as astrophysical, magnetospheric, and solar plasmas. Its applications have grown extensively with large computing powers available such as Pleiades and Blue Water systems in the US. For astrophysical plasmas research PIC method has been utilized in several topics such as reconnection, pulsar, non-relativistic shocks, relativistic shocks, relativistic jets, etc. As one of the research topics in astrophysics, PIC simulations of relativistic jets are reviewed up to the present time with the emphasis on the physics involved in the simulations. In this review we summarize PIC simulations starting with the Weibel instability in slab models of jets and then, continuing with recent progresses on global jets with helical magnetic fields including kinetic Kelvin-Helmholtz instabilities and mushroom instabilities.

scholarly journals Relativistic Jet Simulations of the Weibel Instability in the Slab Model to Cylindrical Jets with Helical Magnetic Fields

2018 ◽  
Author(s):  
Ken-Ichi Nishikawa ◽  
Yosuke Mizuno ◽  
Jose l. Gomez ◽  
Ioana Dutan ◽  
Athina Meli ◽  
...  
Keyword(s):  
Relativistic Jets ◽  
Weibel Instability ◽  
Particle In Cell ◽  
Relativistic Shocks ◽  
Relativistic Jet ◽  
The Us ◽  
Field Geometry ◽  
Solar Plasmas ◽  
Pic Method ◽  
Helical Magnetic Field

The Particle-In-Cell (PIC) method has been developed in order to investigate microscopic phenomena, and with the advances of computing power, newly developed codes have been used for several fields such as astrophysical, magnetospheric, and solar plasmas. PIC applications have grown extensively with large computing powers available on supercomputers such as Pleiades and Blue Waters in the US. For astrophysical plasma research PIC methods have been utilized for several topics such as reconnection, pulsar dynamics, non-relativistic shocks, relativistic shocks, relativistic jets, etc. PIC simulations of relativistic jets have been reviewed with the emphasis on the physics involved in the simulations. This review summarizes PIC simulations, starting with the Weibel instability in slab models of jets, and then focuses on global jet evolution in helical magnetic field geometry. In particular we address kinetic Kelvin-Helmholtz instabilities and mushroom instabilities.

scholarly journals Relativistic Jet Simulations of the Weibel Instability in the Slab Model to Cylindrical Jets with Helical Magnetic Fields

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 29 ◽  
Author(s):  
Ken-Ichi Nishikawa ◽  
Yosuke Mizuno ◽  
Jose Gómez ◽  
Ioana Duţan ◽  
Athina Meli ◽  
...  
Keyword(s):  
Relativistic Jets ◽  
Weibel Instability ◽  
Particle In Cell ◽  
Relativistic Shocks ◽  
Relativistic Jet ◽  
The Us ◽  
Field Geometry ◽  
Solar Plasmas ◽  
Pic Method ◽  
Helical Magnetic Field

The particle-in-cell (PIC) method was developed to investigate microscopic phenomena, and with the advances in computing power, newly developed codes have been used for several fields, such as astrophysical, magnetospheric, and solar plasmas. PIC applications have grown extensively, with large computing powers available on supercomputers such as Pleiades and Blue Waters in the US. For astrophysical plasma research, PIC methods have been utilized for several topics, such as reconnection, pulsar dynamics, non-relativistic shocks, relativistic shocks, and relativistic jets. PIC simulations of relativistic jets have been reviewed with emphasis placed on the physics involved in the simulations. This review summarizes PIC simulations, starting with the Weibel instability in slab models of jets, and then focuses on global jet evolution in helical magnetic field geometry. In particular, we address kinetic Kelvin-Helmholtz instabilities and mushroom instabilities.

scholarly journals PIC methods in astrophysics: simulations of relativistic jets and kinetic physics in astrophysical systems

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Kenichi Nishikawa ◽  
Ioana Duţan ◽  
Christoph Köhn ◽  
Yosuke Mizuno
Keyword(s):  
Plasma Physics ◽  
Magnetic Reconnection ◽  
Laser Plasma ◽  
High Performance ◽  
Relativistic Jets ◽  
Astrophysical Plasmas ◽  
Computing Power ◽  
Particle In Cell ◽  
The Future ◽  
Pic Method

AbstractThe Particle-In-Cell (PIC) method has been developed by Oscar Buneman, Charles Birdsall, Roger W. Hockney, and John Dawson in the 1950s and, with the advances of computing power, has been further developed for several fields such as astrophysical, magnetospheric as well as solar plasmas and recently also for atmospheric and laser-plasma physics. Currently more than 15 semi-public PIC codes are available which we discuss in this review. Its applications have grown extensively with increasing computing power available on high performance computing facilities around the world. These systems allow the study of various topics of astrophysical plasmas, such as magnetic reconnection, pulsars and black hole magnetosphere, non-relativistic and relativistic shocks, relativistic jets, and laser-plasma physics. We review a plethora of astrophysical phenomena such as relativistic jets, instabilities, magnetic reconnection, pulsars, as well as PIC simulations of laser-plasma physics (until 2021) emphasizing the physics involved in the simulations. Finally, we give an outlook of the future simulations of jets associated to neutron stars, black holes and their merging and discuss the future of PIC simulations in the light of petascale and exascale computing.

scholarly journals PARTICLE ACCELERATION, MAGNETIC FIELD GENERATION, AND ASSOCIATED EMISSION IN COLLISIONLESS RELATIVISTIC JETS

2008 ◽  
Vol 17 (10) ◽  
pp. 1761-1767 ◽  
Author(s):  
K.-I. NISHIKAWA ◽  
Y. MIZUNO ◽  
G. J. FISHMAN ◽  
P. HARDEE
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Small Scale ◽  
Spectral Structure ◽  
Relativistic Jets ◽  
Weibel Instability ◽  
Electron Positron ◽  
Jitter Radiation

Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), and galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations using injected relativistic electron-ion (electron-positron) jets show that acceleration occurs within the downstream jet. Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electrons' transverse deflection behind the jet head. The "jitter" radiation from deflected electrons has different properties to synchrotron radiation which assumes a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

Electrostatic particle-in-cell simulation of heat flux mitigation using magnetic fields

2016 ◽  
Vol 82 (5) ◽  
Author(s):  
Karl Felix Lüskow ◽  
S. Kemnitz ◽  
G. Bandelow ◽  
J. Duras ◽  
D. Kahnfeld ◽  
...  
Keyword(s):  
Heat Flux ◽  
Magnetic Fields ◽  
Turbulent Transport ◽  
Optical Emission ◽  
Emission Region ◽  
Transport Channel ◽  
Particle In Cell ◽  
Heat Deposition ◽  
Cell Simulation ◽  
Pic Method

The particle-in-cell (PIC) method was used to simulate heat flux mitigation experiments with partially ionised argon. The experiments demonstrate the possibility of reducing heat flux towards a target using magnetic fields. Modelling using the PIC method is able to reproduce the heat flux mitigation qualitatively. This is driven by modified electron transport. Electrons are magnetised and react directly to the external magnetic field. In addition, an increase of radial turbulent transport is also needed to explain the experimental observations in the model. Close to the target an increase of electron density is created. Due to quasi-neutrality, ions follow the electrons. Charge exchange collisions couple the dynamics of the neutrals to the ions and reduce the flow velocity of neutrals by radial momentum transport and subsequent losses. By this, the dominant heat-transport channel by neutrals gets reduced and a reduction of the heat deposition, similar to the experiment, is observed. Using the simulation a diagnostic module for optical emission is developed and its results are compared with spectroscopic measurements and photos from the experiment. The results of this study are in good agreement with the experiment. Experimental observations such as a shrank bright emission region close to the nozzle exit, an additional emission in front of the target and an overall change in colour to red are reproduced by the simulation.

scholarly journals Particle-in-cell Simulations of Global Relativistic Jets with Helical Magnetic Fields

2016 ◽  
Vol 12 (S324) ◽  
pp. 199-202 ◽  
Author(s):  
Ioana Duţan ◽  
Ken-Ichi Nishikawa ◽  
Yosuke Mizuno ◽  
Jacek Niemiec ◽  
Oleh Kobzar ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
General Structure ◽  
Relativistic Jets ◽  
Particle In Cell ◽  
Electron Positron ◽  
New Findings ◽  
Kinetic Instability ◽  
Composition I ◽  
Helical Magnetic Field ◽  
Kinetic Instabilities

AbstractWe study the interaction of relativistic jets with their environment, using 3-dimen- sional relativistic particle-in-cell simulations for two cases of jet composition: (i) electron-proton (e− − p+) and (ii) electron-positron (e±) plasmas containing helical magnetic fields. 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 and the Mushroom instability. We have found that these kinetic instabilities are suppressed and new types of instabilities can grow. For the e− − p+ jet, a recollimation-like instability occurs and jet electrons are strongly perturbed, whereas for the e± jet, a recollimation-like instability occurs at early times followed by kinetic instability and the general structure is similar to a simulation without a helical magnetic field. We plan to perform further simulations using much larger systems to confirm these new findings.

scholarly journals Weibel instability by ultraintense laser pulses

1999 ◽  
Vol 17 (3) ◽  
pp. 515-518 ◽  
Author(s):  
T. OKADA ◽  
I. SAJIKI ◽  
K. SATOU
Keyword(s):  
Magnetic Fields ◽  
Velocity Distribution ◽  
Electromagnetic Waves ◽  
Laser Pulses ◽  
Electron Velocity ◽  
Electron Velocity Distribution ◽  
Loss Mechanism ◽  
Weibel Instability ◽  
Particle In Cell ◽  
Underdense Plasmas

Particle-in-cell (PIC) simulations show that an anisotropic electron velocity distribution is demonstrated by ultraintense laser pulses in underdense plasmas. Recently, it is reported that the anisotropy has been experimentally demonstrated in laser-produced plasmas. It is also pointed out that gigagauss magnetic fields are generated by ultraintense laser pulses. We have already published that the Weibel-type electromagnetic instabilities can be theoretically excited by electrons in a velocity distribution with anisotropic temperature. If these electromagnetic waves are excited, the target may have a possibility not only to give rise to a new type of energy loss mechanism but also to influence the implosion characteristics. In this work, we present PIC simulation of the interaction of ultraintense laser pulses with plasmas. Intense self-generated magnetic fields is produced by the mechanism of Weibel instability in underdense plasmas.

scholarly journals Kinetic simulations of mildly relativistic shocks – I. Particle acceleration in high Mach number shocks

2019 ◽  
Vol 485 (4) ◽  
pp. 5105-5119 ◽  
Author(s):  
P Crumley ◽  
D Caprioli ◽  
S Markoff ◽  
A Spitkovsky
Keyword(s):  
Particle Acceleration ◽  
Mach Number ◽  
Magnetic Fields ◽  
Thermal Power ◽  
Power Laws ◽  
Maximum Energy ◽  
Magnetic Fluctuations ◽  
Energy Fraction ◽  
Particle In Cell ◽  
Relativistic Shocks

Abstract We use fully kinetic particle-in-cell simulations with unprecedentedly large transverse box sizes to study particle acceleration in weakly magnetized mildly relativistic shocks travelling at a velocity ≈ 0.75c and a Mach number of 15. We examine both subluminal (quasi-parallel) and superluminal (quasi-perpendicular) magnetic field orientations. We find that quasi-parallel shocks are mediated by a filamentary non-resonant (Bell) instability driven by returning ions, producing magnetic fluctuations on scales comparable to the ion gyroradius. In quasi-parallel shocks, both electrons and ions are accelerated into non-thermal power laws whose maximum energy grows linearly with time. The upstream heating of electrons is small, and the two species enter the shock front in rough thermal equilibrium. The shock’s structure is complex; the current of returning non-thermal ions evacuates cavities in the upstream that form filaments of amplified magnetic fields once advected downstream. At late times, 10 per cent of the shock’s energy goes into non-thermal protons and ${\gtrsim }10{{\ \rm per\ cent}}$ into magnetic fields. We find that properly capturing the magnetic turbulence driven by the non-thermal ions is important for properly measuring the energy fraction of non-thermal electrons, εe. We find εe ∼ 5 × 10−4 for quasi-parallel shocks with v = 0.75c, slightly larger than what was measured in simulations of non-relativistic shocks. In quasi-perpendicular shocks, no non-thermal power-law develops in ions or electrons. The ion acceleration efficiency in quasi-parallel shocks suggests that astrophysical objects that could host mildly relativistic quasi-parallel shocks – for example, the jets of active galactic nuclei or microquasars – may be important sources of cosmic rays and their secondaries, such as gamma-rays and neutrinos.

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

2020 ◽  
Vol 493 (2) ◽  
pp. 2652-2658
Author(s):  
Kenichi Nishikawa ◽  
Yosuke Mizuno ◽  
Jose L Gómez ◽  
Ioana Duţan ◽  
Jacek Niemiec ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Reconnection ◽  
Large Radius ◽  
Linear Stage ◽  
Relativistic Jets ◽  
Particle In Cell ◽  
Helical Magnetic Field ◽  
Kinetic Instabilities ◽  
Key Questions

ABSTRACT One of the key questions in the study of relativistic jets is how magnetic reconnection occurs and whether it can effectively accelerate electrons in the jet. We performed 3D particle-in-cell (PIC) simulations of a relativistic electron–proton jet of relatively large radius that carries a helical magnetic field. We focused our investigation on the interaction between the jet and the ambient plasma and explore how the helical magnetic field affects the excitation of 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. At the linear stage we observe recollimation shocks near the centre of the jet. As the electron–proton jet evolves into the deep non-linear stage, the helical magnetic field becomes untangled due to reconnection-like phenomena, and electrons are repeatedly accelerated as they encounter magnetic-reconnection events in the turbulent magnetic field.

scholarly journals RADIATION FROM RELATIVISTIC SHOCKS WITH TURBULENT MAGNETIC FIELDS

2010 ◽  
Vol 19 (06) ◽  
pp. 715-721 ◽  
Author(s):  
K.-I. NISHIKAWA ◽  
J. NIMIEC ◽  
M. MEDVEDEV ◽  
B. ZHANG ◽  
P. HARDEE ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Magnetic Fields ◽  
Weibel Instability ◽  
Pair Plasma ◽  
Nonlinear Stage ◽  
Relativistic Shocks ◽  
Electron Positron ◽  
Ambient Electron

Using our new 3D relativistic electromagnetic particle (REMP) code parallelized with MPI, we investigated long-term particle acceleration associated with a relativistic electron–positron jet propagating in an unmagnetized ambient electron–positron plasma. We have also performed simulations with electron-ion jets. The simulations were performed using a much longer simulation system than our previous simulations in order to investigate the full nonlinear stage of the Weibel instability for electron–positron jets and its particle acceleration mechanism. Cold jet electrons are thermalized and ambient electrons are accelerated in the resulting shocks for pair plasma case. Acceleration of ambient electrons leads to a maximum ambient electron density three times larger than the original value for pair plasmas. Behind the bow shock in the jet shock strong electromagnetic fields are generated. These fields may lead to time-dependent afterglow emission. We calculated radiation from electrons propagating in a uniform parallel magnetic field to verify the technique. We also used the new technique to calculate emission from electrons based on simulations with a small system with two different cases for Lorentz factors (15 and 100). We obtained spectra which are consistent with those generated from electrons propagating in turbulent magnetic fields with red noise. This turbulent magnetic field is similar to the magnetic field generated at an early nonlinear stage of the Weibel instability.

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