English
Related papers

Related papers: Accelerated Lambda Iteration in Rapidly Expanding …

200 papers

A fully implicit finite difference scheme has been developed to solve the hydrodynamic equations coupled with radiation transport. Solution of the time dependent radiation transport equation is obtained using the discrete ordinates method…

Fluid Dynamics · Physics 2008-07-14 Karabi Ghosh , S. V. G. Menon

The linearly-polarized solar limb spectrum that is produced by scattering processes contains a wealth of information on the physical conditions and magnetic fields of the solar outer atmosphere, but the modeling of many of its strongest…

Solar and Stellar Astrophysics · Physics 2015-05-18 M. Sampoorna , J. Trujillo Bueno

With a state-of-the-art numerical method for solving the integral-differential equation of radiative transfer, we investigate the flux of the Ly$\alpha$ photon $\nu_0$ emergent from an optically thick halo containing a central light source.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Ishani Roy , Chi-Wang Shu , Li-Zhi Fang

Having an accurate calibration method is crucial for any scientific research done by a radio telescope. The next generation radio telescopes such as the Square Kilometre Array (SKA) will have a large number of receivers which will produce…

Instrumentation and Methods for Astrophysics · Physics 2018-04-03 Ahmad Mouri Sardarabadi , Alle-Jan van der Veen , Léon V. E. Koopmans

This paper considers the iterative solution of linear systems arising from discretization of the anisotropic radiative transfer equation with discontinuous elements on the sphere. In order to achieve robust convergence behavior in the…

Numerical Analysis · Mathematics 2021-03-11 Jürgen Dölz , Olena Palii , Matthias Schlottbom

We present a new, multi-dimensional implementation of the Advanced Spectral Leakage (ASL) scheme with the purpose of modelling neutrino-matter interactions in neutron star mergers. A major challenge is the neutrino absorption in the…

High Energy Astrophysical Phenomena · Physics 2019-11-06 Davide Gizzi , Evan O'Connor , Stephan Rosswog , Albino Perego , Ruben Cabezón , Lorenzo Nativi

We introduce AREPO-RT, a novel radiation hydrodynamic (RHD) solver for the unstructured moving-mesh code AREPO. Our method solves the moment-based radiative transfer equations using the M1 closure relation. We achieve second order…

Instrumentation and Methods for Astrophysics · Physics 2019-02-13 Rahul Kannan , Mark Vogelsberger , Federico Marinacci , Ryan McKinnon , Rüdiger Pakmor , Volker Springel

Atomically thin two-dimensional (2D) semiconductors are extensively investigated for opto-electronic applications that require strong light-matter interactions. In view of such applications, it is essential to understand how…

Materials Science · Physics 2022-11-16 Pieter Schiettecatte , Zeger Hens , Pieter Geiregat

We describe a photon-conserving radiative transfer algorithm, using a spatially-adaptive ray tracing scheme, and its parallel implementation into the adaptive mesh refinement (AMR) cosmological hydrodynamics code, Enzo. By coupling the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 John H. Wise , Tom Abel

We explore the application of Monte Carlo transport methods to solving coupled radiation-hydrodynamics problems. We use a time-dependent, frequency-dependent, 3-dimensional radiation transport code, that is special relativistic and includes…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 Nathaniel Roth , Daniel Kasen

Scalar wave scattering by many small particles of arbitrary shapes with impedance boundary condition is studied. The problem is solved asymptotically and numerically under the assumptions a << d << lambda, where k = 2pi/lambda is the wave…

Numerical Analysis · Mathematics 2016-02-16 Alexander Ramm , Nhan Tran

The Warm Plasma Dispersion Relation, for waves in the electron cyclotron resonance range of frequencies, can be cast into the form of a bi-quadratic equation for $N_\perp$, where the coefficients are a function of $N_\perp^2$ and an…

Plasma Physics · Physics 2021-02-03 Pim L. Joostens , Egbert Westerhof

Deconvolution algorithms have been used successfully for optimization/restoration/deblurring of astronomical images in a variety of wavelengths, especially in the optical band (e.g., for HST). We present here an iterative Richardson-Lucy…

Astrophysics · Physics 2007-11-15 G. Maurin , A. Djannati-Atai , P. Espigat

We describe the structure and implementation of a radiation hydrodynamic solver for MANGA, the moving-mesh hydrodynamics module of the large-scale parallel code, Charm N-body GrAvity solver (ChaNGa). We solve the equations of time dependent…

Instrumentation and Methods for Astrophysics · Physics 2020-03-04 Philip Chang , Shane W. Davis , Yan-Fei Jiang

We derive new equations using the mixed-frame approach for one- and two-dimensional (axisymmetric) time-dependent radiation transport and the associated couplings with matter. Our formulation is multi-group and multi-angle and includes…

Astrophysics · Physics 2011-02-11 Ivan Hubeny , Adam Burrows

As one of the leading acceleration mechanisms in laser-driven underdense plasmas, direct laser acceleration (DLA) is capable of producing high-energy-density electron beams in a plasma channel for many applications. However, the mechanism…

Plasma Physics · Physics 2021-04-28 F. -Y. Li , P. K. Singh , S. Palaniyappan , C. -K. Huang

This paper is concerned with the development of suitable numerical method for the approximation of discontinuous solutions of parameter-dependent linear hyperbolic conservation laws. The objective is to reconstruct such approximation, for…

Numerical Analysis · Mathematics 2021-09-21 Marie Billaud-Friess , Thomas Heuzé

We perform three dimensional radiation hydrodynamic simulations of the structure and dynamics of radiation dominated envelopes of massive stars at the location of the iron opacity peak. One dimensional hydrostatic calculations predict an…

Solar and Stellar Astrophysics · Physics 2015-11-04 Yan-Fei Jiang , Matteo Cantiello , Lars Bildsten , Eliot Quataert , Omer Blaes

Moving grids are of interest in the numerical solution of hydrodynamical problems and in numerical relativity. We show that conventional integration methods for the simple wave equation in one and more than one dimension exhibit a number of…

Computational Physics · Physics 2009-11-06 Miguel Alcubierre , Bernard F. Schutz

Context. Modern radio astronomical arrays have (or will have) more than one order of magnitude more receivers than classical synthesis arrays, such as the VLA and the WSRT. This makes gain calibration a computationally demanding task.…

Instrumentation and Methods for Astrophysics · Physics 2014-10-09 Stefano Salvini , Stefan J. Wijnholds