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We model the hydrodynamic interaction of a shock wave of an evolved supernova remnant with a small interstellar gas cloud like the ones observed in the Cygnus loop and in the Vela SNR. We investigate the interplay between radiative cooling…

Astrophysics · Physics 2009-11-11 S. Orlando , G. Peres , F. Reale , F. Bocchino , R. Rosner , T. Plewa , A. Siegel

Magneto-hydrodynamic (MHD) Alfv\'en waves have been a focus of laboratory plasma physics and astrophysics for over half a century. Their unique nature makes them ideal energy transporters, and while the solar atmosphere provides…

In the parts of the solar corona and solar wind that experience the fewest Coulomb collisions, the component proton, electron, and heavy ion populations are not in thermal equilibrium with one another. Observed differences in temperatures,…

Solar and Stellar Astrophysics · Physics 2015-06-05 Steven R. Cranmer , Adriaan A. van Ballegooijen

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…

We discuss the generic characteristics of stochastic particle acceleration by a fully developed turbulence spectrum and show that resonant interactions of particles with high speed waves dominate the acceleration process. To produce the…

Astrophysics · Physics 2009-11-13 Siming Liu , Zhong-Hui Fan , Christopher L. Fryer

The temperatures of the heavy ions ($T_i$) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of $T_i$ is usually challenging due to the nonthermal motion,…

Solar and Stellar Astrophysics · Physics 2023-05-17 Yingjie Zhu , Judit Szente , Enrico Landi

We present the first magnetohydrodynamic model of the stellar chromospheric heating and acceleration of the outer atmospheres of cool evolved stars, using alpha Tau as a case study. We used a 1.5D MHD code with a generalized Ohm's law that…

Solar and Stellar Astrophysics · Physics 2014-09-15 V. S. Airapetian , J. E. Leake , K. G. Carpenter

X-ray observations of shock-heated plasmas, such as those found in supernova remnants, often exhibit features of temperature and ionization non-equilibrium. For accurate interpretation of these observations, proper calculations of the…

High Energy Astrophysical Phenomena · Physics 2024-10-02 Yuken Ohshiro , Shunsuke Suzuki , Yoshizumi Okada , Hiromasa Suzuki , Hiroya Yamaguchi

The temperatures of the plasma in the supernova remnants (SNRs) are initially very low just after the shock heating. The electron temperature (kT_{e}) increases quickly by Coulomb interaction, and then the energetic electrons gradually…

High Energy Astrophysical Phenomena · Physics 2021-05-12 Shigeo Yamauchi , Masayoshi Nobukawa , Katsuji Koyama

According to \emph{Wind} observations between June 2004 and May 2019, this Letter investigates the proton and alpha particle temperatures in the space of ($\theta_d$, $V_d/V_A$) for the first time, where $\theta_d$ and $V_d$ are the radial…

Space Physics · Physics 2020-02-05 G. Q. Zhao , H. Q. Feng , D. J. Wu , J. Huang , Y. Zhao , Q. Liu , Z. J. Tian

State-of-the-art MHD calculations reveal acceptable agreement with observational data for the height profile of the temperature $T(h)$ in the transition region of solar corona. Simultaneously, the velocity of the solar wind $U(h)$ has also…

Plasma Physics · Physics 2020-07-29 A. M. Varonov

The cosmic-ray spectrum up to the knee ($E\sim 10^{15}$ eV) is attributed to acceleration processes taking place at the blastwaves which bound supernova remnants. Theoretical predictions give a similar estimate for the maximum energy which…

Astrophysics · Physics 2009-10-31 Eric van der Swaluw , Abraham Achterberg , Yves A. Gallant

In this Letter we use the unprecedented spatial resolution of the Chandra X-ray Observatory to carry out, for the first time, a measurement of the post-shock electron temperature and proper motion of a young SNR, specifically to address…

Astrophysics · Physics 2015-06-24 John P. Hughes , Cara E. Rakowski , Anne Decourchelle

We solve the equations of radiation hydrodynamics in the two-temperature fluid approximation on an adaptive grid. The temperature structure depends upon the electron-ion energy exchange length, $l_{ei}$, and the electron conduction length,…

Astrophysics · Physics 2007-05-23 M W Sincell , M Gehmeyr , D Mihalas

Balmer-dominated shocks in supernova remnants (SNRs) produce strong hydrogen lines with a two-component profile composed of a narrow contribution from cold upstream hydrogen atoms, and a broad contribution from hydrogen atoms that have…

Astrophysics · Physics 2009-11-13 Matthew van Adelsberg , Kevin Heng , Richard McCray , John C. Raymond

We have performed an extensive statistical investigation of how interplanetary fast forward shocks affect certain turbulence parameters, namely, the cross-helicity, $\sigma_c$, residual energy, $\sigma_r$, and magnetic helicity, $\sigma_m$.…

Solar and Stellar Astrophysics · Physics 2025-05-09 Emilia Kilpua , Simon Good , Juska Soljento , Domenico Trotta , Tia Bäcker , Julia Ruohotie , Jens Pomoell , Chaitanya Sishtla , Rami Vainio

Electron acceleration in collisionless shocks with arbitrary magnetic field orientations is discussed. It is shown that the injection of thermal electrons into diffusive shock acceleration process is achieved by an electron beam with a…

High Energy Astrophysical Phenomena · Physics 2010-05-25 Takanobu Amano , Masahiro Hoshino

It has been known for over 50 years that the radio emission from shell supernova remnants (SNRs) indicates the presence of electrons with energies in the GeV range emitting synchrotron radiation. The discovery of nonthermal X-ray emission…

High Energy Astrophysical Phenomena · Physics 2015-05-20 S. P. Reynolds

Supernova remnants (SNRs) are believed to produce the majority of galactic cosmic rays (CRs). SNRs harbor non-relativistic collisionless shocks responsible for acceleration of CRs via diffusive shock acceleration (DSA), in which particles…

High Energy Astrophysical Phenomena · Physics 2022-12-20 Artem Bohdan

While supernova remnants (SNRs) have long been considered prime candidates as sources of cosmic rays, it is only recently that X-ray observations have identified several shell-type SNRs dominated by nonthermal emission, thus revealing…

Astrophysics · Physics 2007-05-23 Patrick Slane