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We present results of three dimensional simulations of the uppermost part of the sun, at 3 stages of its evolution. Each model includes physically realistic radiative-hydrodynamics (the Eddington approximation is used in the optically thin…

Astrophysics · Physics 2007-05-23 F. J. Robinson , P. Demarque , S. Sofia , K. L. Chan , Y. -C. Kim , D. B. Guenther

For hydrodynamic model atmospheres, absolute lineshifts are becoming an observable diagnostic tool beyond the classical ones of line-strength, -width, -shape, and -asymmetry. This is the wavelength displacement of different types of…

Astrophysics · Physics 2007-05-23 Dainis Dravins

We study viscous hydrodynamics of hot conformal field theory plasma with multiple/non-Abelian symmetries in the framework of AdS/CFT correspondence, using a recently proposed method of directly solving bulk gravity in derivative expansion…

High Energy Physics - Theory · Physics 2009-08-14 Mahdi Torabian , Ho-Ung Yee

We address the classical stellar-atmosphere problem and describe our method of numerical solution in detail. The problem consists of the solution of the radiation transfer equation under the constraints of hydrostatic, radiative and…

Astrophysics · Physics 2007-05-23 K. Werner , J. L. Deetjen , S. Dreizler , T. Nagel , T. Rauch , S. L. Schuh

Standing acoustic waves have been known to generate Eulerian time-mean 'streaming' flows at least since the seminal investigation of Lord Rayleigh in the 1880s. Nevertheless, a recent body of numerical and experimental evidence has shown…

Fluid Dynamics · Physics 2024-10-10 Jacques Abdul Massih , Remil Mushthaq , Guillaume Michel , Gregory P. Chini

We present in this paper a multigroup model for radiation hydrodynamics to account for variations of the gas opacity as a function of frequency. The entropy closure model (M1) is applied to multigroup radiation transfer in a radiation…

High Energy Astrophysical Phenomena · Physics 2015-05-27 N. M. H. Vaytet , E. Audit , B. Dubroca , F. Delahaye

Red supergiants are massive evolved stars that contribute extensively to the chemical enrichment of our Galaxy. It has been shown that convection in those stars gives rise to large granules that cause surface inhomogeneities and shock waves…

Solar and Stellar Astrophysics · Physics 2015-05-30 A. Chiavassa , B. Freytag , T. Masseron , B. Plez

This work provides a concrete implementation of E. Fermi's model of particle acceleration in magnetohydrodynamic (MHD) turbulence, connecting the rate of energization to the gradients of the velocity of magnetic field lines, which it…

High Energy Astrophysical Phenomena · Physics 2022-11-30 Martin Lemoine

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

In the presence of an intensive laser field the radiative recombination of the continuum electron into an atomic bound state generally is accompanied by absorption or emission of several laser quanta. The spectrum of emitted photons…

Atomic Physics · Physics 2009-10-31 M. Yu. Kuchiev , V. N. Ostrovsky

We present a geometric multigrid solver for the M1 model of radiative transfer without source terms. In radiative hydrodynamics applications, the radiative transfer needs to be solved implicitly because of the fast propagation speed of…

Numerical Analysis · Mathematics 2022-09-28 Hélène Bloch , Pascal Tremblin , Matthias González , Edouard Audit

A self-consistent nonlinear hydrodynamic theory is presented of the propagation of a long and thin relativistic electron beam, for a typical plasma wake field acceleration configuration in an unmagnetized and overdense plasma. The random…

Plasma Physics · Physics 2017-12-06 Dušan Jovanović , Renato Fedele , Sergio De Nicola , Tamina Akhter , Milivoj Belić

In these proceedings we present recent efforts to understand the energetics of magnetohydrodynamic (MHD) turbulence driven by the magneto-rotational instability (MRI). These studies are carried out in the local (shearing box) approximation…

Astrophysics · Physics 2009-11-10 Thomas A. Gardiner , James M. Stone

This paper describes the design and implementation of our new multi-group, multi-dimensional radiation hydrodynamics (RHD) code Fornax and provides a suite of code tests to validate its application in a wide range of physical regimes.…

Instrumentation and Methods for Astrophysics · Physics 2019-03-06 M. Aaron Skinner , Joshua C. Dolence , Adam Burrows , David Radice , David Vartanyan

We present a co-scaling grid formalism and its implementation in the magnetohydrodynamics code Athena++. The formalism relies on flow symmetries in astrophysical problems involving expansion, contraction, and center-of-mass motion. The grid…

Instrumentation and Methods for Astrophysics · Physics 2021-10-13 Roark Habegger , Fabian Heitsch

We discuss the current implementation of the ALI method into our HYDrodynamical RAdiation(HYDRA) code for rapidly expanding, low density envelopes commonly found in core collapse and thermonuclear supernovae, novae and WR stars. Due to the…

Astrophysics · Physics 2007-05-23 P. Hoeflich

We use our variable Eddington tensor (VET) radiation hydrodynamics code to perform two-dimensional simulations to study the impact of radiation forces on atmospheres composed of dust and gas. Our setup closely follows that of Krumholz &…

Astrophysics of Galaxies · Physics 2015-06-19 Shane W. Davis , Yan-Fei Jiang , James M. Stone , Norman Murray

Context. Supernova remnants are known as sources of galactic cosmic rays for their non-thermal emission of radio waves, X-rays, and gamma-rays. However, the observed soft broken power-law spectra are hard to reproduce within standard…

High Energy Astrophysical Phenomena · Physics 2016-08-31 Robert Brose , Igor Telezhinsky , Martin Pohl

Context. The magnetic field in the solar atmosphere continually reconnects and accelerates charged particles to high energies. Simulations of the atmosphere in three dimensions that include the effects of accelerated particles can aid our…

Solar and Stellar Astrophysics · Physics 2022-10-05 L. Frogner , B. V. Gudiksen

We present a general scheme to approach the space - time evolution of deformations, currents, and the electric field in charge density waves related to appearance of intrinsic topological defects: dislocations, their loops or pairs, and…

Strongly Correlated Electrons · Physics 2021-03-02 Serguei Brazovskii , Natasha Kirova