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We present a new 1-D multi-physics simulation code with use cases intended for, but not limited to, hydrodynamic escapeproblems of planetary atmospheres and planetary accretion models. Our formulation treats an arbitrary number of species…

Earth and Planetary Astrophysics · Physics 2023-05-10 Matthäus Schulik , Richard Booth

Stationary magnetohydrodynamic (MHD) outflows from a rotating, conducting Keplerian accretion disk threaded by B-field are investigated numerically by time-dependent, axisymmetric (2.5D) simulations using a Godunov-type code. A large class…

We present for astrophysical use a multi-dimensional numerical code to solve the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit finite difference method on an Eulerian grid, called the Total Variation Diminishing…

Astrophysics · Physics 2016-08-30 Dongsu Ryu , T. W. Jones , Adam Frank

We present a simulation code which can solve broad ranges of partial differential equations in a full sphere. The code expands tensorial variables in a spectral series of spin-weighted spherical harmonics in the angular directions and a…

Instrumentation and Methods for Astrophysics · Physics 2018-04-26 Daniel Lecoanet , Geoffrey M. Vasil , Keaton J. Burns , Benjamin P. Brown , Jeffrey S. Oishi

Outflows can be loaded and accelerated to high speeds along rapidly rotating, open magnetic field lines by centrifugal forces. Whether such magnetocentrifugally driven winds are stable is a longstanding theoretical problem. As a step…

Astrophysics · Physics 2009-11-11 Jeffrey M. Anderson , Zhi-Yun Li , Ruben Krasnopolsky , Roger D. Blandford

[Abridged] In order to explain the slow rotation observed in a large fraction of accreting pre-main-sequence stars (CTTSs), we explore the role of stellar winds in torquing down the stars. For this mechanism to be effective, the stellar…

Astrophysics · Physics 2009-11-13 Sean Matt , Ralph E. Pudritz

A numerical technique used to solve boundary value problems is modified to find periodic steady-state solutions of nonautonomous dynamical systems. The technique uses a matrix representation of the time derivative obtained through…

Dynamical Systems · Mathematics 2007-05-23 Rafael G. Campos , Gilberto O. Arciniega

We derive semi-analytic solutions for the thermally driven cumulative outflow from a dense stellar cluster that consists of a large number of stars with strong stellar winds, under the key assumption that their mass and energy deposition…

Solar and Stellar Astrophysics · Physics 2025-07-28 Stan Owocki

Observations of collimated outflows in young stellar objects indicate that several features of the jets can be understood by adopting the picture of a two-component outflow, wherein a central stellar component around the jet axis is…

Astrophysics · Physics 2009-11-13 T. Matsakos , K. Tsinganos , N. Vlahakis , S. Massaglia , A. Mignone , E. Trussoni

We present the first-ever simulations of non-ideal magnetohydrodynamical (MHD) stellar winds coupled with disc-driven jets where the resistive and viscous accretion disc is self-consistently described. The transmagnetosonic, collimated MHD…

Astrophysics · Physics 2008-11-26 Fabien Casse , Zakaria Meliani , C. Sauty

We present results of simulations to assess the feasibility of modeling outflows from massive stars using the Los Alamos 3-D radiation hydrodynamics code Cassio developed for inertial confinement fusion (ICF) applications. We find that a…

Solar and Stellar Astrophysics · Physics 2018-06-05 Joyce A. Guzik , Chris Fryer , Todd J. Urbatsch , Stanley P. Owocki

Accurate mass-loss rates and terminal velocities from massive stars winds are essential to obtain synthetic spectra from radiative transfer calculations and to determine the evolutionary path of massive stars. From a theoretical point of…

Solar and Stellar Astrophysics · Physics 2021-04-21 I. Araya , A. Christen , M. Curé , L. S. Cidale , R. O. J. Venero , C. Arcos , A. C. Gormaz-Matamala , M. Haucke , P. Escárate , H. Clavería

We use two-dimensional axisymmetric magnetohydrodynamic simulations to compute steady-state solutions for solar-like stellar winds from rotating stars with dipolar magnetic fields. Our parameter study includes 50 simulations covering a wide…

Solar and Stellar Astrophysics · Physics 2015-06-05 Sean P. Matt , Keith B. MacGregor , Marc H. Pinsonneault , Thomas P. Greene

We derive semi-analytic solutions for optically thick, super-Eddington stellar winds, induced by an assumed steady energy addition $\Delta {\dot E}$ concentrated around a near-surface heating radius $R$ in a massive star of central…

Solar and Stellar Astrophysics · Physics 2017-11-08 Stanley P. Owocki , Richard H. D. Townsend , Eliot Quataert

We solve the anisotropic diffusion equation in 2D, where the dominant direction of diffusion is defined by a vector field which does not conform to a Cartesian grid. Our method uses operator splitting to separate the diffusion perpendicular…

Numerical Analysis · Mathematics 2023-03-29 Dean Muir , Kenneth Duru , Matthew Hole , Stuart Hudson

In this paper, we introduce a method of imposing asymmetric conditions on the velocity vector with respect to independent variables and a method of moving frame for solving the three dimensional Navier-Stokes equations. Seven families of…

Fluid Dynamics · Physics 2007-06-28 Xiaoping Xu

We review the numerical modelling of the nonlinear pulsations of classical variable stars with hydrocodes that include the effects of turbulent convection. Despite their simplicity these turbulent convective recipes appear to remove many of…

Astrophysics · Physics 2007-05-23 J. Robert Buchler

We study mass outflows driven from accretion discs by radiation pressure due to spectral lines. To investigate non-axisymmetric effects, we use the Athena++ code and develop a new module to account for radiation pressure driving. In 2D, our…

High Energy Astrophysical Phenomena · Physics 2018-02-13 Sergei Dyda , Daniel Proga

Numerical simulations of magneto-convection have greatly expanded our understanding of stellar interiors and stellar magnetism. Recently, fully compressible hydrodynamical simulations of full-star models have demonstrated the feasibility of…

Solar and Stellar Astrophysics · Physics 2022-08-03 José R. Canivete Cuissa , Romain Teyssier

Nonlinear diffusion equations of spectral transfer are systematically derived for anisotropic magnetohydrodynamics in the regime of wave turbulence. The background of the analysis is the asymptotic Alfv\'en wave turbulence equations from…

Solar and Stellar Astrophysics · Physics 2015-05-19 Sebastien Galtier , Eric Buchlin