English
Related papers

Related papers: Numerical Solution of the Expanding Stellar Atmosp…

200 papers

We introduce a numerical method for the numerical solution of the so-called Lur'e matrix equations that arise in balancing-related model reduction and linear-quadratic infinite time horizon optimal control. Based on the fact that the set of…

Numerical Analysis · Mathematics 2011-01-07 Federico Poloni , Timo Reis

Recent years have seen a huge development in spatial modelling and prediction methodology, driven by the increased availability of remote-sensing data and the reduced cost of distributed-processing technology. It is well known that…

Computation · Statistics 2020-02-18 Andrew Zammit-Mangion , Jonathan Rougier

We present a class of new explicit and stable numerical algorithms to solve the spatially discretized linear heat or diffusion equation. After discretizing the space and the time variables like conventional finite difference methods, we do…

Numerical Analysis · Mathematics 2021-04-27 Endre Kovács

The calculation of the emerging radiation from a model atmosphere requires knowledge of the emissivity and absorption coefficients, which are proportional to the atomic level population densities of the levels involved in each transition.…

Instrumentation and Methods for Astrophysics · Physics 2024-09-25 D. Arramy , J. de la Cruz Rodríguez , J. Leenaarts

The program package SME (Spectroscopy Made Easy), designed to perform an analysis of stellar spectra using spectral fitting techniques, was updated due to adding new functions (isotopic and hyperfine splittins) in VALD and including grids…

Instrumentation and Methods for Astrophysics · Physics 2017-10-31 N. Piskunov , T. Ryabchikova , Yu. Pakhomov , T. Sitnova , S. Alexeeva , L. Mashonkina , T. Nordlander

The nonlinear space-fractional problems often allow multiple stationary solutions, which can be much more complicated than the corresponding integer-order problems. In this paper, we systematically compute the solution landscapes of…

Numerical Analysis · Mathematics 2022-08-31 Bing Yu , Lei Zhang , Pingwen Zhang , Xiangcheng Zheng

Different relaxation approximations to partial differential equations, including conservation laws, Hamilton-Jacobi equations, convection-diffusion problems, gas dynamics problems, have been recently proposed. The present paper focuses onto…

Numerical Analysis · Mathematics 2007-05-23 Fausto Cavalli , Matteo Semplice

We provide a numerical algorithm for the model characterizing anomalous diffusion in expanding media, which is derived in [F. Le Vot, E. Abad, and S. B. Yuste, Phys. Rev. E {\bf96} (2017) 032117]. The Sobolev regularity for the equation is…

Numerical Analysis · Mathematics 2020-11-13 Daxin Nie , Jing Sun , Weihua Deng

This paper studies the numerical methods to approximate the solutions for a sort of McKean-Vlasov neutral stochastic differential delay equations (MV-NSDDEs) that the growth of the drift coefficients is super-linear. First, We obtain that…

Probability · Mathematics 2022-11-04 Yuanping Cui , Xiaoyue Li , Yi Liu , Chenggui Yuan

This paper presents two approaches to mathematical modelling of a synthetic seismic pulse, and a comparison between them. First, a new analytical model is developed in two-dimensional Cartesian coordinates. Combined with an initial…

Geophysics · Physics 2020-12-01 S. J. Walters , L. K. Forbes , A. M. Reading

This study aims to provide an analytical scheme for computing equilibrium configurations of relativistic stars by solving the Tolman-Oppenheimer-Volkoff equations directly in isotropic polar coordinates, as opposed to the commonly applied…

General Relativity and Quantum Cosmology · Physics 2024-06-12 Dániel Barta

The recent results attained from a thermodynamically conceived numerical scheme applied on wave propagation in viscoelastic/rheological solids are generalized here, both in the sense that the scheme is extended to four spacetime dimensions…

Classical Physics · Physics 2024-03-08 Áron Pozsár , Mátyás Szücs , Róbert Kovács , Tamás Fülöp

The model and algorithm for the cooling of the magnetized neutron stars are presented. The cooling evolution described by system of parabolic partial differential equations with non-linear coefficients is solved using Alternating Direction…

Computational Physics · Physics 2016-03-07 H. Grigorian , A. Ayriyan , E. Chubarian , A. Piloyan , M. Rafayelyan

We solve the integral equation describing the propagation of light in an isothermal plane-parallel atmosphere of optical thickness $\tau^*$, adopting a uniform thermalization parameter $\epsilon$. The solution given by the ALI method,…

Astrophysics · Physics 2007-05-23 L. Chevallier , F. Paletou , B. Rutily

In this article, we discuss the numerical solution of diffusion equations on random surfaces within the isogeometric framework. We describe in detail, how diffusion problems on random surfaces can be modelled and how quantities of interest…

Numerical Analysis · Mathematics 2022-04-28 Wei Huang , Michael Multerer

The modeling of atmospheric processes in the context of weather and climate simulations is an important and computationally expensive challenge. The temporal integration of the underlying PDEs requires a very large number of time steps,…

Numerical Analysis · Mathematics 2020-01-03 Francois P. Hamon , Martin Schreiber , Michael L. Minion

Convection schemes are a large source of error in global weather and climate models, and modern resolutions are often too fine to parameterise convection but are still too coarse to fully resolve it. Recently, numerical solutions of…

Numerical Analysis · Mathematics 2020-06-24 William A McIntyre , Hilary Weller , Christopher E Holloway

In this paper we study the application of a simplified method to solve the dynamic radiative transfer problem in expanding envelopes. The method, which requires a computational effort similar to that of the diffusion approximation, is based…

Astrophysics · Physics 2009-10-28 J. Gomez-Gomar , J. Isern

The time-dependent one-dimensional nonlinear Schr\"odinger equation (NLSE) is solved numerically by a hybrid pseudospectral-variational quantum algorithm that connects a pseudospectral step for the Hamiltonian term with a variational step…

A flexible model is developed for multivariate generalized spherical distributions, i.e. ones with level sets that are star shaped. To work in dimension above 2 requires tools from computational geometry and multivariate numerical…

Computation · Statistics 2015-10-26 John P Nolan