Physics and Phenomenology of Weakly Magnetized, Relativistic Astrophysical Shock Waves

Vanthieghem, Arno; Lemoine, Martin; Plotnikov, Illya; Grassi, Anna; Grech, M.; Grémillet, L.; Pelletier, G.

doi:10.3390/galaxies8020033

Cited by 33 publications

(25 citation statements)

References 124 publications

(222 reference statements)

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“…In this simulation a relativistic jet is injected into an ambient plasma as shown in Fig. 8a, therefore the shock structures are different from those that are obtained when using numerical schemes with reflecting boundary conditions (e.g., Vanthieghem et al 2020).…”

Section: Injection Schemementioning

confidence: 93%

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

Nishikawa¹,

Duţan

Köhn

et al. 2021

Living Rev Comput Astrophys

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The 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.

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Section: Injection Schemementioning

confidence: 93%

“…In these settings the backward (reverse) shock is degenerated to an FS. Recently, Vanthieghem et al (2020) reviewed physics and phenomenology of weakly magnetized, relativistic astrophysical shock waves in the reflected scheme.…”

Section: Weibel Instabilities With Various Flavoursmentioning

confidence: 99%

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

Nishikawa¹,

Duţan

Köhn

et al. 2021

Living Rev Comput Astrophys

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“…In the fully relativistic regime, meaning a shock Lorentz factor γ sh 3 − 5, particle acceleration appears restricted to the weakly magnetised limit, σ 10 −3 (see e.g., Vanthieghem et al 2020 and references therein). Strictly speaking, this result applies to super-luminal shocks, but highly relativistic shocks are generically super-luminal as a consequence of the Lorentz boost (a factor γ sh ) of the perpendicular magnetic field components in the shock rest frame.…”

Section: Fixing Parameters From the Microphysics Of Shock Accelerationmentioning

confidence: 99%

“…The acceleration timescale is given by t acc t scatt in relativistic shocks, where t scatt denotes the scattering timescale, which departs from the Bohm regime (t scatt ∝ r L ) at weak magnetisation (Vanthieghem et al 2020, and references therein). Consequently, the radiative limit can be written γ e,max ∼ 10 7 n e /1 cm −3 −1/6…”

Section: Fixing Parameters From the Microphysics Of Shock Accelerationmentioning

confidence: 99%

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Electron-proton co-acceleration on relativistic shocks in extreme-TeV blazars

Zech

Lemoine

2021

A&A

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Aims. The multi-wavelength emission from a newly identified population of ‘extreme-TeV’ blazars, with Compton peak frequencies around 1 TeV, is difficult to interpret with standard one-zone emission models. Large values of the minimum electron Lorentz factor and quite low magnetisation values seem to be required. Methods. We propose a scenario where protons and electrons are co-accelerated on internal or recollimation shocks inside the relativistic jet. In this situation, energy is transferred from the protons to the electrons in the shock transition layer, leading naturally to a high minimum Lorentz factor for the latter. A low magnetisation favours the acceleration of particles in relativistic shocks. Results. The shock co-acceleration scenario provides additional constraints on the set of parameters of a standard one-zone lepto-hadronic emission model, reducing its degeneracy. Values of the magnetic field strength of a few mG and minimum electron Lorentz factors of 103 to 104, required to provide a satisfactory description of the observed spectral energy distributions of extreme blazars, result here from first principles. While acceleration on a single standing shock is sufficient to reproduce the emission of most of the extreme-TeV sources we have examined, re-acceleration on a second shock appears needed for those objects with the hardest γ-ray spectra. Emission from the accelerated proton population, with the same number density as the electrons but in a lower range of Lorentz factors, is strongly suppressed. Satisfactory self-consistent representations were found for the most prominent representatives of this new blazar class.

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Multi-scale simulations of particle acceleration in astrophysical systems

Marcowith

Ferrand

Grech

et al. 2020

Living Rev Comput Astrophys

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This review aims at providing an up-to-date status and a general introduction to the subject of the numerical study of energetic particle acceleration and transport in turbulent astrophysical flows. The subject is also complemented by a short overview of recent progresses obtained in the domain of laser plasma experiments. We review the main physical processes at the heart of the production of a non-thermal distribution in both Newtonian and relativistic astrophysical flows, namely the first and second order Fermi acceleration processes. We also discuss shock drift and surfing acceleration, two processes important in the context of particle injection in shock acceleration. We analyze with some details the particle-in-cell (PIC) approach used to describe particle kinetics. We review the main results obtained with PIC simulations in the recent years concerning particle acceleration at shocks and in reconnection events. The review discusses the solution of Fokker–Planck problems with application to the study of particle acceleration at shocks but also in hot coronal plasmas surrounding compact objects. We continue by considering large scale physics. We describe recent developments in magnetohydrodynamic (MHD) simulations. We give a special emphasis on the way energetic particle dynamics can be coupled to MHD solutions either using a multi-fluid calculation or directly coupling kinetic and fluid calculations. This aspect is mandatory to investigate the acceleration of particles in the deep relativistic regimes to explain the highest cosmic ray energies.

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Physics and Phenomenology of Weakly Magnetized, Relativistic Astrophysical Shock Waves

Cited by 33 publications

References 124 publications

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

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

Electron-proton co-acceleration on relativistic shocks in extreme-TeV blazars

Multi-scale simulations of particle acceleration in astrophysical systems

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