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With the advent of the Square Kilometre Array Observatory (SKAO), scientists will be able to directly observe the Epoch of Reionization by mapping the distribution of neutral hydrogen at different redshifts. While physically motivated…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-10 Damien Korber , Michele Bianco , Emma Tolley , Jean-Paul Kneib

We develop a positivity-preserving finite difference WENO scheme for the Ten-Moment equations with body forces acting as a source in the momentum and energy equations. A positive forward Euler scheme under a CFL condition is first…

Numerical Analysis · Mathematics 2019-10-11 Asha Kumari Meena , Rakesh Kumar , Praveen Chandrashekar

Photoionization of an atom in the presence of a neighboring atom of different species is studied. The latter first undergoes resonant photoexcitation, leading to an autoionizing state of the diatomic system. Afterwards, the excitation…

Atomic Physics · Physics 2020-08-11 F. Grüll , A. B. Voitkiv , C. Müller

A substantial fraction of all ionizing photons originate from radiative recombinations. However, in radiative transfer calculations this recombination radiation is often assumed to be absorbed 'on-the-spot' because for most methods the…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-01 Milan Raičević , Andreas H. Pawlik , Joop Schaye , Alireza Rahmati

Our aim is to determine the dominant processes and timescales for the ionisation equilibrium of calcium under solar chromospheric conditions. The study is based on numerical simulations with the RADYN code, which includes hydrodynamics,…

Solar and Stellar Astrophysics · Physics 2015-05-27 Sven Wedemeyer-Böhm , Mats Carlsson

Heat diffusion has been widely used in brain imaging for surface fairing, mesh regularization and cortical data smoothing. Motivated by diffusion wavelets and convolutional neural networks on graphs, we present a new fast and accurate…

Computer Vision and Pattern Recognition · Computer Science 2020-01-20 Shih-Gu Huang , Ilwoo Lyu , Anqi Qiu , Moo K. Chung

The ocean front has an important impact in many areas, it is meaningful to obtain accurate ocean front positioning, therefore, ocean front detection is a very important task. However, the traditional edge detection algorithm does not detect…

Computer Vision and Pattern Recognition · Computer Science 2019-09-18 Qingyang Li , Guoqiang Zhong , Cui Xie

The weighted essentially non-oscillatory {technique} using a stencil of $2r$ points (WENO-$2r$) is an interpolatory method that consists in obtaining a higher approximation order from the non-linear combination of interpolants of $r+1$…

Numerical Analysis · Mathematics 2024-04-26 Pep Mulet , Juan Ruiz-Alvarez , Chi-Wang Shu , Dionisio F. Yáñez

We introduce a new general-purpose time-dependent ionisation network (IN) and a radiation transport (RT) module in the magneto-hydrodynamic (MHD) code PLUTO. Our ionisation network is reliable for temperatures ranging from 5e3 to 3e8 K, and…

Astrophysics of Galaxies · Physics 2021-03-17 Kartick Chandra Sarkar , Amiel Sternberg , Orly Gnat

Precise temperature measurements on systems of few ultracold atoms is of paramount importance in quantum technologies, but can be very resource-intensive. Here, we put forward an adaptive Bayesian framework that substantially boosts the…

We introduce DiffFNO, a novel diffusion framework for arbitrary-scale super-resolution strengthened by a Weighted Fourier Neural Operator (WFNO). Mode Rebalancing in WFNO effectively captures critical frequency components, significantly…

Computer Vision and Pattern Recognition · Computer Science 2025-04-08 Xiaoyi Liu , Hao Tang

Due to its excellent shock-capturing capability and high resolution, the WENO scheme family has been widely used in varieties of compressive flow simulation. However, for problems containing strong shocks and contact discontinuities, such…

Fluid Dynamics · Physics 2019-01-15 Jun Peng , Chuanlei Zhai , Guoxi Ni , Yiqing Shen , Heng Yong

We present a comprehensive analytical study of radiative transfer using the method of moments and include the effects of non-isotropic scattering in the coherent limit. Within this unified formalism, we derive the governing equations and…

Earth and Planetary Astrophysics · Physics 2015-06-19 Kevin Heng , João M. Mendonça , Jae-Min Lee

We present a data-driven, differentiable neural network model designed to learn the temperature field, its gradient, and the cooling rate, while implicitly representing the melt pool boundary as a level set in laser powder bed fusion. The…

Diffusion models have risen as a powerful tool in robotics due to their flexibility and multi-modality. While some of these methods effectively address complex problems, they often depend heavily on inference-time obstacle detection and…

Ion transport, often described by the Poisson--Nernst--Planck (PNP) equations, is ubiquitous in electrochemical devices and many biological processes of significance. In this work, we develop conservative, positivity-preserving, energy…

Numerical Analysis · Mathematics 2020-07-15 Jie Ding , Zhongming Wang , Shenggao Zhou

In this work, a near-wall model, which couples the inverse of a recently developed compressible velocity transformation [Griffin, Fu, & Moin, PNAS, 118:34, 2021] and an algebraic temperature-velocity relation, is developed for high-speed…

Fluid Dynamics · Physics 2023-09-11 Kevin Patrick Griffin , Lin Fu , Parviz Moin

We present Compressible Atmospheric Model-Network (CAM-NET), an AI model designed to predict neutral atmospheric variables from the Earth's surface to the ionosphere with high accuracy and computational efficiency. Accurate modeling of the…

Space Physics · Physics 2025-07-03 Jiahui Hu , Wenjun Dong

In this paper, we introduce a superconvergent approximation method that employs radial basis functions (RBFs) in the numerical solution of conservation laws. The use of RBFs for interpolation and approximation is a well developed area of…

Numerical Analysis · Mathematics 2021-06-21 Andrew Christlieb , William Sands , Hyoseon Yang

Excitonic models of light-harvesting complexes, where the vibrational degrees of freedom are treated as a bath, are commonly used to describe the motion of the electronic excitation through a molecule. Recent experiments point toward the…

Quantum Physics · Physics 2011-07-19 Christoph Kreisbeck , Tobias Kramer , Mirta Rodriguez , Birgit Hein