相关论文: Electron-Ion Temperature Equilibration at Collisio…
A novel collisionless shock jump condition is suggested by modeling the entropy production at the shock transition region. We also calculate downstream developments of the atomic ionization balance and the ion temperature relaxation in…
A goal of supernova remnant (SNR) evolution models is to relate fundamental parameters of a supernova (SN) explosion and progenitor star to the current state of its SNR. The SNR hot plasma is characterized by its observed X-ray spectrum,…
Recent advances in the understanding of the properties of supernova remnant shocks have been precipitated by the Chandra and XMM X-ray Observatories, and the HESS Atmospheric Cerenkov Telescope in the TeV band. A critical problem for this…
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…
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…
Heating of charged particles via collisionless shocks, while ubiquitous in the universe, is an intriguing yet puzzling plasma phenomenon. One outstanding question is how electrons and ions approach an equilibrium after they were heated to…
We present Chandra X-ray images of Tycho's supernova remnant that delineate its outer shock as a thin, smooth rim along the straight northeastern edge and most of the circular western half. The images also show that the Si and S ejecta are…
A collisionless shock may be strongly modified by the presence of neutral atoms through the processes of charge exchange between ions and neutrals and ionization of the latter. These two processes lead to exchange of energy and momentum…
We have developed an inversion method for determination of the characteristics of the acceleration mechanism directly and non-parametrically from observations, in contrast to the usual forward fitting of parametric model variables to…
Aims: We want to probe the physics of fast collision-less shocks in supernova remnants. In particular, we are interested in the non-equilibration of temperatures and particle acceleration. Specifically, we aim to measure the oxygen…
Supernova remnants (SNRs) are believed to be the major contributors to Galactic cosmic rays. The detection of non-thermal emission from SNRs demonstrates the presence of energetic particles, but direct signatures of protons and other ions…
The identification of pre-acceleration mechanisms for cosmic ray ions in supernova remnant shocks is an important problem in astrophysics. Recent particle-in-cell (PIC) shock simulations have shown that inclusion of the full electron…
Thermal electrons cannot directly participate in the process of diffusive acceleration at electron-ion shocks because their Larmor radii are smaller than the shock transition width: this is the well-known electron injection problem of…
We present numerical simulations of the evolution of a supernova (SN) remnant expanding into a uniform background medium with density $n_H = 1.0$ cm$^{-3}$ and temperature of $10^4$ K. We include a dynamically evolving non-equilibrium…
Collisionless shock waves, found in supernova remnants, interstellar, stellar, and planetary environments, and laboratories, are one of nature's most powerful particle accelerators. This study combines in situ satellite measurements with…
We discuss a method to calculate with quantum molecular dynamics simulations the rate of energy exchanges between electrons and ions in two-temperature plasmas, liquid metals and hot solids. Promising results from this method were recently…
Over-ionized, recombining plasma is an emerging class of X-ray bright supernova remnants (SNRs). This unique thermal state where the ionization temperature ($T_{\rm z}$) is significantly higher than the electron temperature ($T_{\rm e}$) is…
Precise measurements of galactic cosmic rays revealed a significant difference between the rigidity spectral indices of protons and helium ions. This finding is a notable contrast to the commonly accepted theoretical prediction that…
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…
The supernova remnant (SNR) RCW86 is among the few SNRs with Balmer-emission lines containing broad and narrow spectral components that trace fast, non-radiative shocks in partially-ionized gas.\ These are invaluable laboratories for…