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New high-resolution spectropolarimetric observations of solar prominences require improved radiative modelling capabilities in order to take into account both multi-dimensional - at least 2D - geometry and complex atomic models. This makes…

Astrophysics · Physics 2009-11-13 L. Leger , L. Chevallier , F. Paletou

An effective radiative divertor maximizes the utilization of atomic processes to spread out the energy deposition to the divertor chamber walls and to reduce the peak heat flux. Because the mixture of neutral atoms and ions in the divertor…

plasm-ph · Physics 2009-10-28 A. S. Wan , H. E. Dalhed , H. A. Scott , D. E. Post , T. D. Rognlien

We provide a fully nonlinear port-Hamiltonian formulation for discrete elastodynamical systems as well as a structure-preserving time discretization. The governing equations are obtained in a variational manner and represent index-1…

Dynamical Systems · Mathematics 2025-06-23 Philipp L. Kinon , Tobias Thoma , Peter Betsch , Paul Kotyczka

In this paper we present a multilevel projection-based iterative scheme for solving thermal radiative transfer problems that performs iteration cycles on the high-order Boltzmann transport equation (BTE) and low-order moment equations.…

Numerical Analysis · Mathematics 2026-03-18 Joseph M. Coale , Dmitriy Y. Anistratov

We employ a generalization of Einstein's random walk paradigm for diffusion to derive a class of multidimensional degenerate nonlinear parabolic equations in non-divergence form. Specifically, in these equations, the diffusion coefficient…

Analysis of PDEs · Mathematics 2023-07-14 Ivan C. Christov , Isanka Garli Hevage , Akif Ibraguimov , Rahnuma Islam

We examine the non-equilibrium radiative heat transfer between a plate and finite cylinders and cones, making the first accurate theoretical predictions for the total heat transfer and the spatial heat flux profile for three-dimensional…

Classical Physics · Physics 2015-05-28 Alexander P. McCauley , M. T. Homer Reid , Matthias Krüger , Steven G. Johnson

This work aims to describe a mathematical model and a numerical method to simulate a thin anisotropic composite membrane moving and deforming in 3D space under a dynamic load of an arbitrary time and space profile. The model and the method…

Numerical Analysis · Mathematics 2020-07-24 Vitalii Aksenov , Alexey Vasyukov , Igor Petrov

We present a model for nonlinear decay of the weak wave in three-dimensional incompressible magnetohydrodynamic (MHD) turbulence. We show that the decay rate is different for parallel and perpendicular waves. We provide a general formula…

Astrophysics · Physics 2010-11-11 Andrey Beresnyak , Alex Lazarian

The propagation of a quasi-harmonic electromagnetic wave in a bulk hyperbolic dielectric metamaterial is considered. If the group velocities dispersion is not taken into account, then wave propagation can be described either by the…

Pattern Formation and Solitons · Physics 2022-11-04 A. I. Maimistov

In this paper, we present a systematic stability analysis of the quadrature-based moment method (QBMM) for the one-dimensional Boltzmann equation with BGK or Shakhov models. As reported in recent literature, the method has revealed its…

Numerical Analysis · Mathematics 2018-12-21 Qian Huang , Shuiqing Li , Wen-An Yong

In this paper, we consider an inverse problem for a nonlinear wave equation with a damping term and a general nonlinear term. This problem arises in nonlinear acoustic imaging and has applications in medical imaging and other fields. The…

Analysis of PDEs · Mathematics 2023-03-01 Yang Zhang

We prove finite speed of propagation for the multiplicative stochastic wave equation in two and three dimensions which leads us to a global space-time well-posedness result for the cubic nonlinear equation in the analogue of the energy…

Analysis of PDEs · Mathematics 2021-10-18 Immanuel Zachhuber

The SP3 approximation of the neutron transport equation allows improving the accuracy for both static and transient simulations for reactor core analysis compared with the neutron diffusion theory. Besides, the SP3 calculation costs are…

Computational Engineering, Finance, and Science · Computer Science 2019-03-28 Alexander V. Avvakumov , Valery F. Strizhov , Petr N. Vabishchevich , Alexander O. Vasilev

We present a ray-tracing technique for radiative transfer modeling of complex three-dimensional (3D) structures which include dense regions of high optical depth like in dense molecular clouds, circumstellar disks, envelopes of evolved…

Astrophysics · Physics 2009-11-11 J. Steinacker , A. Bacmann , Th. Henning

This paper concerns periodic solutions for a 1D-model with nonlocal velocity given by the periodic Hilbert transform. There is a rich literature showing that this model presents singular behavior of solutions via numerics and mathematical…

Analysis of PDEs · Mathematics 2014-10-14 Lucas C. F. Ferreira , Julio C. Valencia-Guevara

The transport equations for polarized radiation transfer in non-Riemannian, Weyl-Cartan type space-times are derived, with the effects of both torsion and non-metricity included. To obtain the basic propagation equations we use the tangent…

General Relativity and Quantum Cosmology · Physics 2009-11-11 K. S. Cheng , T. Harko , X. Y. Wang

The non-local hydrodynamic moment equations for compressible convection are compared to numerical simulations. Convective and radiative flux typically deviate less than 20% from the 3D simulations, while mean thermodynamic quantities are…

Astrophysics · Physics 2009-10-31 F. Kupka

The present paper reviews recent advances in the theory of nonlinear driven magnetohydrodynamic (MHD) waves in slow and Alfven resonant layers. Simple estimations show that in the vicinity of resonant positions the amplitude of variables…

Solar and Stellar Astrophysics · Physics 2015-05-20 Istvan Ballai , Michael Ruderman

We develop a model for spiral galaxies based on a nonlinear realization of the Newtonian dynamics starting from the momentum and mass conservations in the phase space. The radial solution exhibits a rotation curve in qualitative accordance…

Astrophysics · Physics 2009-09-15 C. A. M. de Melo , S. T. Resende

In this paper we investigate the three-dimensional (3D) motion of a test particle in a stationary, axially symmetric spacetime around a central compact object, under the influence of a radiation field. To this aim we extend the…

General Relativity and Quantum Cosmology · Physics 2019-11-05 Vittorio De Falco , Pavel Bakala , Emmanuele Battista , Debora Lančová , Maurizio Falanga , Luigi Stella