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We discuss the temperature distribution in a two-dimensional, thermally unstable numerical simulation of the warm and cold gas in the Galactic disk, including the magnetic field, self-gravity, the Coriolis force, stellar energy injection…

Astrophysics · Physics 2009-11-06 A. Gazol , E. Vazquez-Semadeni , F. J. Sanchez-Salcedo , J. Scalo

We have chosen a reduced set of 18 ionization rate equations (for ions of H, C, N, O, S and Ne), which allow us to obtain a moderately accurate estimate of the non-equilibrium radiative cooling function. We evaluate the accuracy of this…

Astrophysics · Physics 2009-10-28 A. Raga , G. Mellema , P. Lundqvist

Previous experiments have revealed that shock waves in thermally relaxing gases, such as ionizing, dissociating and vibrationally excited gases, can become unstable. To date, the mechanism controlling this instability has not been resolved.…

Pattern Formation and Solitons · Physics 2012-02-06 Matei I. Radulescu , Nick Sirmas

Collisional self-interactions occurring in protostellar jets give rise to strong shocks, the structure of which can be affected by radiative cooling within the flow. To study such colliding flows, we use the AstroBEAR AMR code to conduct…

High Energy Astrophysical Phenomena · Physics 2022-12-13 R. N. Markwick , A. Frank , J. Carroll-Nellenback , B. Liu , E. G. Blackman , S. V. Lebedev , P. M. Hartigan

We present a general formulation for stability analyses of radiative shocks with multiple cooling processes, longitudinal and transverse perturbations, and unequal electron and ion temperatures. Using the accretion shocks of magnetic…

Astrophysics · Physics 2009-11-06 Curtis J. Saxton , Kinwah Wu

In the absence of magnetic fields and cosmic rays, radiative cooling laws with a range of dependences on temperature affect the stability of interstellar gas. For about four and a half decades, astrophysicists have recognised the importance…

Astrophysics of Galaxies · Physics 2011-08-08 T. W. Hartquist , A. Y. Wagner , S. A. E. G. Falle , J. M. Pittard , S. Van Loo

We review recent results on the nonlinear development of thermal instability in the context of the turbulent atomic interstellar medium (ISM). First, we pre- sent a brief summary of the linear theory, remarking that, in the atomic ISM, the…

Heating of virialized gas by streaming cosmic rays (CRs) may be energetically important in galaxy halos, groups and clusters. We present a linear thermal stability analysis of plasmas heated by streaming CRs. We separately treat equilibria…

Astrophysics of Galaxies · Physics 2020-02-24 Philipp Kempski , Eliot Quataert

Previous experiments have revealed that shock waves driven through dissipative gases may become unstable, for example, in granular gases, and in molecular gases undergoing strong relaxation effects. The mechanisms controlling these…

Soft Condensed Matter · Physics 2015-02-03 Nick Sirmas , Matei I. Radulescu

We present laboratory results on energy partitioning from supercritical, magnetized collisionless shock experiments ($\rm{M_A} \sim 8$, $\rm{M_{ms}}\sim 4$). We report the first observation of fully-developed laboratory shocks that evolve…

Within a quasiparticle framework, we reconsider the issue of computing the Bose-Einstein condensation temperature ($T_c$) in a weakly non-ideal Bose gas. The main result of this and previous investigations is that $T_c$ increases with the…

Condensed Matter · Physics 2007-05-23 Masudul Haque , Andrei E. Ruckenstein

We discuss high-resolution simulations of one-dimensional, plane-parallel shock waves with mean speeds between 150 and 240 km/s propagating into gas with Alfven velocities up to 40 km/s and outline the conditions under which these radiative…

Astrophysics · Physics 2009-10-30 Paul A. Kimoto , David F. Chernoff

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…

High Energy Astrophysical Phenomena · Physics 2024-05-16 Masahiro Ichihashi , Aya Bamba , Yuichi Kato , Satoru Katsuda , Hiromasa Suzuki , Tomoaki Kasuga , Hirokazu Odaka , Kazuhiro Nakazawa

We perform numerical analyses of the structure induced by gravitational instabilities in cooling gaseous accretion discs. For low enough cooling rates a quasi-steady configuration is reached, with the instability saturating at a finite…

Astrophysics · Physics 2009-11-13 Peter Cossins , Giuseppe Lodato , Cathie Clarke

Nonrelativistic electrostatic unmagnetized shocks are frequently observed in laboratory plasmas and they are likely to exist in astrophysical plasmas. Their maximum speed, expressed in units of the ion acoustic speed far upstream of the…

Plasma Physics · Physics 2015-06-15 ME Dieckmann , H Ahmed , G Sarri , D Doria , I Kourakis , L Romagnani , M Pohl , M Borghesi

We investigate thermal regime of the baryons behind shock waves arising in the process of virialization of dark matter halos. We find a fraction of the shocked gas cooled by radiation of HD molecules down to the temperature of the cosmic…

Astrophysics · Physics 2007-05-23 E. O. Vasiliev , Yu. A. Shchekinov

To model the temperature evolution of optically thin astrophysical environments at MHD scales, radiative and collisional cooling rates are typically either pre-tabulated or fit into a functional form and then input into MHD codes as a…

Solar and Stellar Astrophysics · Physics 2025-08-14 Amanda Stricklan , Tim Waters , James Klimchuk

Thermal regime of the baryons behind shock waves arising in the process of virialization of dark matter halos is governed at cetrain conditions by radiation of HD lines. A small fraction of the shocked gas can cool down to the temperature…

Astrophysics · Physics 2011-08-31 E. O. Vasiliev , Yu. A. Shchekinov

The analysis of Balmer-dominated optical spectra from non-radiative (adiabatic) SNRs has shown that the ratio of the electron to proton temperature temperature at the blast wave is close to unity at v_s <= 400 km/s, but declines sharply…

Astrophysics · Physics 2009-11-11 Parviz Ghavamian , J. Martin Laming , Cara E. Rakowski

In this paper we present computations of the integrated metal-ion column densities produced in the post-shock cooling layers behind fast, radiative shock-waves. For this purpose, we have constructed a new shock code that calculates the…

Astrophysics · Physics 2011-02-11 Orly Gnat , Amiel Sternberg