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In this paper we introduce a general framework for defining and studying essentially non-oscillatory reconstruction procedures of arbitrarily high order accuracy, interpolating data in a central stencil around a given computational cell…

Numerical Analysis · Mathematics 2018-07-09 I. Cravero , G. Puppo , M. Semplice , G. Visconti

Accurate modeling of heat flux in inertial confinement fusion plasmas requires closures that remain predictive far from local equilibrium and across disparate spatial and temporal resolutions. We develop a resolution-independent…

Plasma Physics · Physics 2026-04-07 M. Luo , A. R. Bell , F. Miniati , S. M. Vinko , G. Gregori

In this work, high-order discrete well-balanced methods for one-dimensional hyperbolic systems of balance laws are proposed. We aim to construct a method whose discrete steady states correspond to solutions of arbitrary high-order ODE…

Numerical Analysis · Mathematics 2025-01-13 Maria Kazolea , Carlos Parés Madroñal , Mario Ricchiuto

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 2008-04-04 F. Cavalli , M. Semplice

Source localization is the inverse problem of graph information dissemination and has broad practical applications. However, the inherent intricacy and uncertainty in information dissemination pose significant challenges, and the ill-posed…

Machine Learning · Computer Science 2023-04-19 Bosong Huang , Weihao Yu , Ruzhong Xie , Jing Xiao , Jin Huang

Using high redshift radio sources as background, the 21cm forest observations probe the neutral hydrogen absorption signatures of early structures along the lines of sight. Directly sensitive to the spin temperature, it complements the 21cm…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 Yidong Xu , Xuelei Chen , Zuhui Fan , Hy Trac , Renyue Cen

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

We consider in this contribution a simplified idealized one-dimensional model in a nuclear core reactor coupling the diffusion equation on the neutron flux withthe enthalpy equation for the water which collects the heat produced by this…

Numerical Analysis · Mathematics 2025-03-11 Olivier Lafitte , François Dubois

Quantum computers have the potential to deliver speed-ups for solving certain important problems that are intractable for classical counterparts, making them a promising avenue for advancing modern computation. However, many quantum…

Quantum Physics · Physics 2025-12-23 Kang-Min Hu , Min Namkung , Hyang-Tag Lim

In this paper, we combine the nonlinear HWENO reconstruction in \cite{newhwenozq} and the fixed-point iteration with Gauss-Seidel fast sweeping strategy, to solve the static Hamilton-Jacobi equations in a novel HWENO framework recently…

Numerical Analysis · Mathematics 2021-12-15 Yupeng Ren , Yulong Xing , Jianxian Qiu

We present an extension to the short-characteristic ray-tracing and non-equilibrium photon-ionization code C2Ray. The new version includes the effects of helium and improved multi-frequency heating. The motivation for this work is to be…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Martina M. Friedrich , Garrelt Mellema , Ilian T. Iliev , Paul R. Shapiro

Cosmological simulations of reionization often treat radiative transfer by solving for the monopole and dipoles of the intensity field and by making ansatz for the quadrupole moments to close the system of equations. We investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-03 Xiaohan Wu , Matthew McQuinn , Daniel Eisenstein

Non-equilibrium ionization (NEI) is essentially required for astrophysical plasma diagnostics once the plasma status departs from ionization equilibrium assumptions. In this work, we perform fast NEI calculations combined with…

Solar and Stellar Astrophysics · Physics 2023-02-08 Chengcai Shen , John C. Raymond , Nicholas A. Murphy

A novel type of particle "cooling", called Ionization Cooling, is applicable to slow (v of the order of 0.1c) ions stored in a small ring. The many traversals through a thin foil enhance the nuclear reaction probability, in a steady…

High Energy Physics - Phenomenology · Physics 2011-05-18 C. Rubbia , A. Ferrari , Y. Kadi , V. Vlachoudis

A photoionized gas in thermal equilibrium can display a thermal instability, with 3 or more solutions in the multi-branch region of the S-shape curve giving the temperature versus the radiation-to-gas-pressure ratio. Many studies have been…

Astrophysics · Physics 2009-11-11 A. C. Goncalves , S. Collin , A. -M. Dumont , L. Chevallier

We present a spectrally accurate fast algorithm for evaluating the solution to the scalar wave equation in free space driven by a large collection of point sources in a bounded domain. With $M$ sources temporally discretized by $N_t$ time…

Numerical Analysis · Mathematics 2025-11-27 Nour G. Al Hassanieh , Alex H. Barnett , Leslie Greengard

We develop an asymptotic preserving scheme for the gray radiative transfer equation. Two asymptotic regimes are considered: one is a diffusive regime described by a nonlinear diffusion equation for the material temperature; the other is a…

Numerical Analysis · Mathematics 2019-09-17 Min Tang , Li Wang , Xiaojiang Zhang

We present a novel mapping approach for WENO schemes through the use of an approximate constant mapping function which is constructed by employing an approximation of the classic signum function. The new approximate constant mapping…

Numerical Analysis · Mathematics 2022-02-04 Ruo Li , Wei Zhong

Full Waveform Inversion (FWI) is an inverse problem for estimating the wave velocity distribution in a given domain, based on observed data on the boundaries. The inversion is computationally demanding because we are required to solve…

Machine Learning · Computer Science 2024-05-29 Matan Goren , Eran Treister

In this paper, we empirically reveal an invariance over images-images share a set of one-way wave equations with latent speeds. Each image is uniquely associated with a solution to these wave equations, allowing for its reconstruction with…

Computer Vision and Pattern Recognition · Computer Science 2024-10-17 Yinpeng Chen , Dongdong Chen , Xiyang Dai , Mengchen Liu , Yinan Feng , Youzuo Lin , Lu Yuan , Zicheng Liu