Electron acceleration in supernova remnants

Bohdan, Artem

doi:10.1088/1361-6587/aca5b2

Cited by 13 publications

(5 citation statements)

References 67 publications

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“…This can be accomplished by specular reflection, through the so-called shock-drift acceleration (SDA) by a combination of SDA and DSA [17,32], or by a kind of micro DSA (µ-DSA, [33]). As already said, the acceleration of electrons is less easier to understand [9,34], but they should generally go through the similar pre-acceleration process and once they reach the injection momentum of protons, they will continue to behave in the same fashion and further accelerate through the DSA mechanism.…”

Section: The κ-Distributionmentioning

confidence: 99%

Non-linear diffusive shock acceleration: A recipe for injection of electrons

Арбутина

Zeković

2021

Astroparticle Physics

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Section: The κ-Distributionmentioning

confidence: 99%

Non-linear diffusive shock acceleration: A recipe for injection of electrons

Арбутина

Zeković

2021

Astroparticle Physics

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“…For particles, especially electrons, to undergo DSA, they need to be preaccelerated to acquire enough energy to diffuse across the shock. This preacceleration is necessary because the shock front acts as a barrier that particles need to overcome in order to enter the acceleration process (Treumann 2009;Bohdan 2023).…”

Section: Introductionmentioning

confidence: 99%

Nonthermal Acceleration of Electrons, Positrons, and Protons at a Nonrelativistic Quasi-parallel Collisionless Shock

Yu,

Xia,

Fang

2024

ApJ

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Energetic positrons have been observed in the interstellar medium, and high-energy positrons with relativistic energies up to approximately 1 TeV have been detected in Galactic cosmic rays. We conducted a study on the acceleration of particles, specifically positrons, in a nonrelativistic quasi-parallel collisionless shock induced by a plasma consisting of protons, electrons, and positrons. The positron-to-proton number density ratio in the plasma is 0.1. We focused on a representative shock with a sonic Mach number of 17.1 and an Alfvénic Mach number of 16.8 in the rest frame of the shock. To investigate the acceleration mechanisms of particles including positrons in the shock, we utilized 1D particle-in-cell simulations. It was found that all three species of particles in the shock can be accelerated and exhibit power-law spectra. At the shock front, a significant portion of incoming upstream particles are reflected and undergo significant energy increases, and these reflected particles can be efficiently injected into the process of diffusive shock acceleration (DSA). Moveover, the reflected positrons can be further accelerated by an electric field parallel to the magnetic field when they move along the magnetic field upstream of the shock. As a result, positrons can be preferentially accelerated to be injected in the DSA process compared to electrons.

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“…For this reason, they must undergo some pre-acceleration mechanism before being injected into DSA, which is known as the electron injection problem. Possible mechanisms and the underlying microphysics of electron acceleration have been extensively investigated (see Amano et al 2022;Bohdan 2023 for a review). To interpret the broadband emission from SNRs, MHD simulations coupled with a prescription of particle acceleration have been utilized (see, e.g., Orlando et al 2021, for a review).…”

Section: Introductionmentioning

confidence: 99%

Kinetic Simulations of Nonrelativistic High-mach-number Perpendicular Shocks Propagating in a Turbulent Medium

Fulat,

Bohdan,

Torralba Paz

et al. 2023

ApJ

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Strong nonrelativistic shocks are known to accelerate particles up to relativistic energies. However, for diffusive shock acceleration, electrons must have a highly suprathermal energy, implying the need for very efficient preacceleration. Most published studies consider shocks propagating through homogeneous plasma, which is an unrealistic assumption for astrophysical environments. Using 2D3V particle-in-cell simulations, we investigate electron acceleration and heating processes at nonrelativistic high-Mach-number shocks in electron-ion plasma with a turbulent upstream medium. For this purpose, slabs of plasma with compressive turbulence are simulated separately and then inserted into shock simulations, which require matching of the plasma slabs at the interface. Using a novel procedure of matching electromagnetic fields and currents, we perform simulations of perpendicular shocks setting different intensities of density fluctuations (≲10%) in the upstream region. The new simulation technique provides a framework for studying shocks propagating in turbulent media. We explore the impact of the fluctuations on electron heating, the dynamics of upstream electrons, and the driving of plasma instabilities. Our results indicate that while the presence of turbulence enhances variations in the upstream magnetic field, their levels remain too low to significantly influence the behavior of electrons at perpendicular shocks.

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Electron acceleration in supernova remnants

Cited by 13 publications

References 67 publications

Non-linear diffusive shock acceleration: A recipe for injection of electrons

Non-linear diffusive shock acceleration: A recipe for injection of electrons

Nonthermal Acceleration of Electrons, Positrons, and Protons at a Nonrelativistic Quasi-parallel Collisionless Shock

Kinetic Simulations of Nonrelativistic High-mach-number Perpendicular Shocks Propagating in a Turbulent Medium

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