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The aim of this work is to investigate and characterise particle behaviour in an (observationally-driven) 3D MHD model of the solar atmosphere above a slowly evolving, non-flaring active region. We use a relativistic guiding-centre particle…

Solar and Stellar Astrophysics · Physics 2016-02-17 J. Threlfall , Ph. -A. Bourdin , T. Neukirch , C. E. Parnell

We present PHLEGETHON, a fully compressible, Eulerian magnetohydrodynamic (MHD) code designed for multidimensional simulations in stellar astrophysics. The code uses a time-explicit, second-order, finite-volume method optimized to model a…

Computation of a grid of self consistent 1D model atmospheres of cool stars, sub-stellar objects and exoplanets in the effective temperature range 300K to 3000K, including cloud formation, chemical non-equilibrium effects, and stellar…

We perform cosmological, hydrodynamic simulations of magnetic fields in galaxy clusters. The computational code combines the special-purpose hardware Grape for calculating gravitational interaction, and smooth-particle hydrodynamics for the…

Astrophysics · Physics 2007-05-23 Klaus Dolag , Matthias Bartelmann , Harald Lesch

A program has been designed for accurately generating a potential magnetic field on a staggered grid by extrapolating the magnetic field normal to the photospheric surface. The code first calculates a magnetic potential using the Green's…

Solar and Stellar Astrophysics · Physics 2022-01-06 Callum M. Boocock , David Tsiklauri

We have invented a new algorithm to use with self-gravitating SPH Star Formation codes. The new method is designed to enable SPH simulations to self-regulate their numerical resolution, i.e. the number of SPH particles; the latter is…

Astrophysics · Physics 2007-05-23 Spyridon Kitsionas

The sunspot penumbra is a transition zone between the strong vertical magnetic field area (sunspot umbra) and the quiet Sun. The penumbra has a fine filamentary structure that is characterized by magnetic field lines inclined toward the…

Solar and Stellar Astrophysics · Physics 2010-12-02 I. N. Kitiashvili , A. G. Kosovichev , N. N. Mansour , A. A. Wray

A high-precision two-dimensional stellar evolution code has been developed for studying solar variability due to structural changes produced by varying internal magnetic fields of arbitrary configurations. Specifically, we are interested in…

Astrophysics · Physics 2009-11-11 L. H. Li , P. Ventura , S. Basu , S. Sofia , P. Demarque

Maps of the radial magnetic field at a heliocentric distance of ten solar radii are used as boundary conditions in the MHD code CRONOS to simulate a 3D inner-heliospheric solar wind emanating from the rotating Sun out to 1 AU. The input…

Space Physics · Physics 2013-03-19 T. Wiengarten , J. Kleimann , H. Fichtner , R. Cameron , J. Jiang , R. Kissmann , K. Scherer

Electromagnetic effects play an important role in many phenomena such as isospin-symmetry breaking in the hadron spectrum and the hadronic contributions to g-2. We have generalized the MILC QCD code to include the electromagnetic field. In…

High Energy Physics - Lattice · Physics 2014-11-18 Ran Zhou , Steven Gottlieb

We present a practical guide to Smoothed Particle Hydrodynamics (\SPH) and its application to astrophysical problems. Although remarkably robust, \SPH\ must be used with care if the results are to be meaningful since the accuracy of \SPH\…

Astrophysics · Physics 2007-05-23 T. J. Martin , F. R. Pearce , P. A. Thomas

An Eulerian TVD code and a Lagrangian SPH code are used to simulate the off-axis collision of equal-mass main sequence stars in order to address the question of whether stellar mergers can produce a remnant star where the interior has been…

Astrophysics · Physics 2008-11-26 Hy Trac , Alison Sills , Ue-Li Pen

Electromagnetic slot models are employed to efficiently simulate electromagnetic penetration through openings in an otherwise closed electromagnetic scatterer. Such models, which incorporate varying assumptions about the geometry of the…

Computational Physics · Physics 2025-05-12 Brian A. Freno , Neil R. Matula , Robert A. Pfeiffer , Vinh Q. Dang

In space weather studies and forecasting we employ magnetohydrodynamic (MHD) simulations which can provide rather accurate reconstruction of the solar wind dynamics and its evolution. However, all MHD simulations are restricted by the input…

Solar and Stellar Astrophysics · Physics 2023-06-14 G. M. Shaifullah , J. Magdalenic , C. Tiburzi , I. Jebaraj , E. Samara , P. Zucca

We describe a three-dimensional, Godunov-type numerical magnetohydrodynamics (MHD) method designed for studying disk accretion to a rotating magnetized star in the general case where the star's rotation axis, its magnetic moment, and the…

Astrophysics · Physics 2009-11-07 A. V. Koldoba , M. M. Romanova , G. V. Ustyugova , R. V. E. Lovelace

Context: Thermal conductivity provides important contributions to the energy evolution of the upper solar atmosphere, behaving as a non-linear concentration-dependent diffusion equation. Recently, different methods have been offered as…

Solar and Stellar Astrophysics · Physics 2024-12-11 George Cherry , Boris Gudiksen , Mikolaj Szydlarski

We discuss cosmological hydrodynamic simulations of galaxy formation performed with the new moving-mesh code AREPO, which promises higher accuracy compared with the traditional SPH technique that has been widely employed for this problem.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Dusan Keres , Mark Vogelsberger , Debora Sijacki , Volker Springel , Lars Hernquist

Stellar collisions are an important formation channel for blue straggler stars in globular and old open clusters. Hydrodynamical simulations have shown that the remnants of such collisions are out of thermal equilibrium, are not strongly…

Astrophysics · Physics 2009-11-13 E. Glebbeek , O. R. Pols , J. R. Hurley

We present results of global 3D MHD simulations of disk accretion to a rotating star with dipole and more complex magnetic fields using a Godunov-type code based on the "cubed sphere" grid developed earlier in our group. We describe the…

Solar and Stellar Astrophysics · Physics 2009-01-28 Marina M. Romanova , Alexander V. Koldoba , Galina V. Ustyugova , Akshay K. Kulkarni , Min Long , Richard V. E. Lovelace

We report the first three-dimensional radiation magnetohydrodynamic (RMHD) simulations of protostellar collapse with and without Ohmic dissipation.We take into account many physical processes required to study star formation processes,…

Solar and Stellar Astrophysics · Physics 2015-03-20 Kengo Tomida , Kohji Tomisaka , Tomoaki Matsumoto , Yasunori Hori , Satoshi Okuzumi , Masahiro N. Machida , Kazuya Saigo