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It is thought that solar energetic ions associated with coronal/interplanetary shock waves are accelerated to high energies by the diffusive shock acceleration mechanism. For this mechanism to be efficient, intense magnetic turbulence is…

Solar and Stellar Astrophysics · Physics 2023-11-29 A. Afanasiev , R. Vainio , D. Trotta , S. Nyberg , N. Talebpour Sheshvan , H. Hietala , N. Dresing

Weakly magnetized, relativistic collisionless shock waves are not only the natural offsprings of relativistic jets in high-energy astrophysical sources, they are also associated with some of the most outstanding displays of energy…

High Energy Astrophysical Phenomena · Physics 2020-12-17 A. Vanthieghem , M. Lemoine , I. Plotnikov , A. Grassi , M. Grech , L. Gremillet , G. Pelletier

We investigate the dynamics of an Alfven surface (where the Alfven speed equals the advection velocity) in the context of core collapse supernovae during the phase of accretion on the proto-neutron star. Such a surface should exist even for…

Solar and Stellar Astrophysics · Physics 2015-05-19 Jerome Guilet , Thierry Foglizzo , Sebastien Fromang

We model the propagation of a coronal shock wave, using nonlinear geometrical acoustics. The method is based on the Wentzel-Kramers-Brillouin (WKB) approach and takes into account the main properties of nonlinear waves: i) dependence of the…

Solar and Stellar Astrophysics · Physics 2015-03-19 A. N. Afanasyev , A. M. Uralov

A particle acceleration mechanism by radiation pressure of precursor waves in a relativistic shock is studied. For a relativistic, perpendicular shock with the upstream bulk Lorentz factor of $\gamma_1 \gg 1$, large amplitude…

Astrophysics · Physics 2009-11-13 Masahiro Hoshino

Plasma processes close to SNR shocks result in the amplification of magnetic fields and in the acceleration of electrons, injecting them into the diffusive acceleration mechanism. The acceleration of electrons and the B field amplification…

High Energy Astrophysical Phenomena · Physics 2015-06-09 M E Dieckmann , G Murphy , A Meli , L O C Drury

Electron injection process at high Mach number collisionless quasi-perpendicular shock waves is investigated by means of one-dimensional electromagnetic particle-in-cell simulations. We find that energetic electrons are generated through…

Astrophysics · Physics 2011-02-11 T. Amano , M. Hoshino

The aim of the present study is to shed light on the effects connected with thermal misbalance due to non-equal cooling and heating rates induced by density and temperature perturbations in solar active regions hosting either propagating…

Solar and Stellar Astrophysics · Physics 2022-07-21 S. A. Belov , S. Vasheghani Farahani , N. E. Molevich

We study the escape of cosmic-ray (CR) protons accelerated at a supernova remnant (SNR) by numerically solving a diffusion-convection equation from the vicinity of the shock front to the region far away from the front. We consider the…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Yutaka Fujita , Fumio Takahara , Yutaka Ohira , Kazunari Iwasaki

Alfv\'en waves are responsible for the transfer of magnetic energy in the magnetized plasma. They are involved in heating solar atmosphere and driving solar wind through various nonlinear processes. Since the magnetic field configurations…

Solar and Stellar Astrophysics · Physics 2020-08-04 Takahito Sakaue , Kazunari Shibata

We show that the coronal heating and the fast solar wind acceleration in the coronal holes are natural consequence of the footpoint fluctuations of the magnetic fields at the photosphere, by performing one-dimensional magnetohydrodynamical…

Astrophysics · Physics 2009-11-11 Takeru K. Suzuki , Shu-ichiro Inutsuka

Cosmological hydrodynamic simulations of large scale structure in the universe have shown that accretion shocks and merger shocks form due to flow motions associated with the gravitational collapse of nonlinear structures. Estimated speed…

Astrophysics · Physics 2015-06-24 Hyesung Kang , T. W. Jones

The solar wind emanates from the hot and tenuous solar corona. Earlier studies using 1.5 dimensional simulations show that Alfv\'{e}n waves generated in the photosphere play an important role in coronal heating through the process of…

Solar and Stellar Astrophysics · Physics 2015-05-30 Takuma Matsumoto , Takeru Ken Suzuki

There is a growing evidence that extended radio halos are most likely generated by electrons reaccelerated via some kind of turbulence generated in the cluster volume during major mergers. It is well known that Alfv\'en waves channel most…

Astrophysics · Physics 2014-10-13 Gianfranco Brunetti , Pasquale Blasi , Rossella Cassano , Stefano Gabici

Recent observations have demonstrated that waves which are capable of carrying large amounts of energy are ubiquitous throughout the solar corona. However, the question of how this wave energy is dissipated (on which time and length scales)…

Solar and Stellar Astrophysics · Physics 2014-11-20 Jiajia Liu , Scott W. McIntosh , Ineke De Moortel , James Threlfall , Christian Bethge

We model the diffusive shock acceleration of particles in a system of two colliding shock waves and present a method to solve the time-dependent problem analytically in the test-particle approximation and high energy limit. In particular,…

High Energy Astrophysical Phenomena · Physics 2020-05-06 Thibault Vieu , Stefano Gabici , Vincent Tatischeff

Cosmic rays are charged particles that are accelerated to relativistic speeds by astrophysical shocks. Numerical models have been successful in confirming the acceleration process for (quasi-)parallel shocks, which have the magnetic field…

High Energy Astrophysical Phenomena · Physics 2024-07-09 Allard Jan van Marle , Artem Bohdan , Anabella Araudo , Fabien Casse , Alexandre Marcowith

This work presents a model for generating nonthermal power-law tails of particles' energy probability density functions in turbulent collisionless plasmas, applicable to both non-relativistic and relativistic scenarios. We propose that…

Plasma Physics · Physics 2026-05-05 Stanislav Boldyrev , Daniel Humphrey , Vadim Roytershteyn

The Alfv\'en wave energy flux in the corona can be explored using the electron density and velocity amplitude of the waves. The velocity amplitude of Alfv\'en waves can be obtained from the non-thermal velocity of the spectral line…

Solar and Stellar Astrophysics · Physics 2019-07-03 Girjesh R. Gupta , G. Del Zanna , H. E. Mason

When the pressure of particles accelerated at shock waves is no longer negligible compared to the kinetic pressure of the gas, the linear theory of diffusive shock acceleration breaks down. This is expected in particular when the shock…

High Energy Astrophysical Phenomena · Physics 2021-12-22 Thibault Vieu , Stefano Gabici , Vincent Tatischeff