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Strong non-relativistic shocks are known to accelerate particles up to relativistic energies. However, for Diffusive Shock Acceleration electrons must have a highly suprathermal energy, implying a need for very efficient pre-acceleration.…

Plasma Physics · Physics 2023-10-24 Karol Fulat , Artem Bohdan , Gabriel Torralba Paz , Martin Pohl

Internal shocks provide a plausible heating mechanism in the jets of gamma-ray bursts (GRBs). Shocks occurring below the jet photosphere are mediated by radiation. It was previously found that radiation mediated shocks (RMSs) inside GRB…

High Energy Astrophysical Phenomena · Physics 2019-07-17 Christoffer Lundman , Andrei Beloborodov

We study processes occurring after a sudden heating of the chromosphere at the flare arcade footpoints which is assumed to be caused by particle beams. For the numerical simulations we adopt a 2-D magnetohydrodynamic (MHD) model, in which…

Solar and Stellar Astrophysics · Physics 2019-05-01 P. Jelínek , M. Karlický

We develop a formalism for the identification and accurate estimation of the strength of structure formation shocks during cosmological smoothed particle hydrodynamics simulations. Shocks not only play a decisive role for the thermalization…

Astrophysics · Physics 2009-11-11 Christoph Pfrommer , Volker Springel , Torsten A. Ensslin , Martin Jubelgas

The formation of shocks within the solar atmosphere remains one of the few observable signatures of energy dissipation arising from the plethora of magnetohydrodynamic waves generated close to the solar surface. Active region observations…

Recent experiments claimed that the enhancement of catalytic reaction rates occurs via the reduction of activation barriers driven by non-equilibrium (``hot'') electrons in plasmonic metal nanoparticles. These experiments place plasmonic…

Chemical Physics · Physics 2020-04-22 Yonatan Sivan , Ieng Wai Un , Yonatan Dubi

We simulate several magnetic reconnection processes in the low solar chromosphere/photosphere, the radiation cooling, heat conduction and ambipolar diffusion are all included. Our numerical results indicate that both the high temperature($…

Solar and Stellar Astrophysics · Physics 2016-12-14 Lei Ni , Jun Lin , Ilia I. Roussev , Brigitte Schmieder

The absence of large cooling flows in cool core clusters appears to require self-regulated energy feedback by active galactic nuclei (AGNs) but the exact heating mechanism has not yet been identified. Here, we analyse whether a combination…

Astrophysics of Galaxies · Physics 2017-04-27 Svenja Jacob , Christoph Pfrommer

Our aim is to study the thermal and dynamical evolution of protoplanetary disks in global simulations, including the physics of radiation transfer and magneto-hydrodynamic (MHD) turbulence caused by the magneto-rotational instability. We…

Earth and Planetary Astrophysics · Physics 2015-06-17 M. Flock , S. Fromang , M. González , B. Commerçon

Anisotropic thermal conduction plays an important role in various astrophysical systems. One of the most stringent tests of thermal conduction can be found in supernova remnants. In this paper we study anisotropic thermal conduction and…

Astrophysics · Physics 2007-11-14 D. S. Balsara , D. A. Tilley , J. C. Howk

Production of heat shock proteins are induced when a living cell is exposed to a rise in temperature. The heat shock response of protein DnaK synthesis in E.coli for temperature shifts from temperature T to T plus 7 degrees, respectively to…

Condensed Matter · Physics 2009-10-31 Kristine Bourke Arnvig , Steen Pedersen , Kim Sneppen

Cosmological shock waves play an important role in hierarchical structure formation by dissipating and thermalizing kinetic energy of gas flows, thereby heating the universe. Furthermore, identifying shocks in hydrodynamical simulations and…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-05 Kevin Schaal , Volker Springel

In this paper, we show a "proof of concept" of the heating mechanism of the solar chromosphere due to wave dissipation caused by the effects of partial ionization. Numerical modeling of non-linear wave propagation in a magnetic flux tube,…

Solar and Stellar Astrophysics · Physics 2016-03-16 S. Shelyag , E. Khomenko , A. de Vicente , D. Przybylski

Magnetohydrodynamic (MHD) simulations of the solar atmosphere are often performed under the assumption that the plasma is fully ionized. However, in the lower solar atmosphere a reduced temperature often results in only the partial…

Solar and Stellar Astrophysics · Physics 2022-11-09 Conor D. MacBride , David B. Jess , Elena Khomenko , Samuel D. T. Grant

Aims. The goal of the paper is to present a detailed study of the propagation of low velocity (5 to 25 km s-1) stationary molecular shocks in environments illuminated by an external ultraviolet (UV) radiation field. In particular, we intend…

Hawking showed that the radiation emitted from a classical collapsing shell is thermal. Here, we show that a semiclassical collapsing shell emits radiation that is only approximately thermal, with small but significant deviations. The most…

High Energy Physics - Theory · Physics 2015-06-15 Ram Brustein , A. J. M. Medved

The solar atmosphere is known to contain many different types of wavelike oscillation. Waves and other fluctuations (e.g., turbulent eddies) are believed to be responsible for at least some of the energy transport and dissipation that heats…

Solar and Stellar Astrophysics · Physics 2023-08-09 Steven R. Cranmer , Momchil E. Molnar

Cold ($T\sim 10^{4} \ \mathrm{K}$) gas is very commonly found in both galactic and cluster halos. There is no clear consensus on its origin. Such gas could be uplifted from the central galaxy by galactic or AGN winds. Alternatively, it…

Astrophysics of Galaxies · Physics 2018-07-10 Suoqing Ji , S. Peng Oh , Michael McCourt

Heat conduction plays an important role in the balance between heating and cooling in many astrophysical objects, e.g. cooling flows in clusters of galaxies. Here we investigate the effect of heat conduction on the interaction between a…

Astrophysics · Physics 2009-11-11 E. Meyer-Hofmeister , F. Meyer

Dissipation of magnetohydrodynamic (MHD) wave energy has been proposed as a viable heating mechanism in the solar chromospheric plasma. Here, we use a simplified one-dimensional model of the chromosphere to theoretically investigate the…

Solar and Stellar Astrophysics · Physics 2015-09-23 Roberto Soler , Marc Carbonell , Jose Luis Ballester