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Cosmic ray electron (CRE) acceleration and cooling are important physical processes in astrophysics. We develop an approximative framework to treat CRE physics in the parallel smoothed particle hydrodynamics code Gadget-3. In our…

High Energy Astrophysical Phenomena · Physics 2019-12-03 Dongchao Zheng , Weitian Li , Zhenghao Zhu , Chenxi Shan , Jiajun Zhang , Linfeng Xiao , Xiaoli Lian , Dan Hu

Cosmic rays (CRs) are an integral part of the non-thermal pressure budget in the interstellar medium (ISM) and are the leading-order ionization mechanism in cold molecular clouds. We study the impacts that different microphysical CR…

Identification of nonlinear dynamical systems is crucial across various fields, facilitating tasks such as control, prediction, optimization, and fault detection. Many applications require methods capable of handling complex systems while…

Machine Learning · Statistics 2024-11-05 Luc Brogat-Motte , Riccardo Bonalli , Alessandro Rudi

We present an efficient algorithm to follow spectral evolution of Cosmic Rays (CR) coupled with an MHD system on Eulerian grids. The algorithm is designed for studies of CR energy spectrum evolution in MHD simulations of a galactic…

High Energy Astrophysical Phenomena · Physics 2021-03-17 Mateusz Ogrodnik , Michał Hanasz , Dominik Wóltański

Cosmic rays (CRs) are ubiquitous in the interstellar medium (ISM) of nearby galaxies, but many of their properties are not well-constrained. Gamma-ray observations provide a powerful tool in this respect, allowing us to constrain both the…

High Energy Astrophysical Phenomena · Physics 2023-07-19 Maria Werhahn , Philipp Girichidis , Christoph Pfrommer , Joseph Whittingham

We examine the validity of the Fokker-Planck equation with linear force coefficients as an approximation to the kinetic equation of nucleation in homogeneous isothermal multicomponent condensation. Starting with a discrete equation of…

Classical Physics · Physics 2021-10-04 Yuri S. Djikaev , Eli Ruckenstein , Mark Swihart

The problem of anomalous diffusion in momentum space is considered for plasma-like systems on the basis of a new collision integral, which is appropriate for consideration of the probability transition function (PTF) with long tails in…

Statistical Mechanics · Physics 2015-05-18 S. A. Trigger , W. Ebeling , G. J. F. van Heijst , P. P. J. M. Schram , I. M. Sokolov

The spatial distribution of cosmic ray (CR) particles in the interstellar medium (ISM) is of major importance in radio astronomy, where its knowledge is essential for the interpretation of observations, and in theoretical astrophysics,…

Astrophysics of Galaxies · Physics 2023-06-28 Devika Tharakkal , Andrew P. Snodin , Graeme R. Sarson , Anvar Shukurov

A correct description of cosmic-ray (CR) diffusion in turbulent plasma is essential for many astrophysical and heliospheric problems. This paper aims to present physical diffusion behavior of CRs in actual turbulent magnetic fields, model…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Siyao Xu , Huirong Yan

We present a numerical method to accurately simulate particle size distributions within the formalism of rate equation cluster dynamics. This method is based on a discretization of the associated Fokker-Planck equation. We show that…

Materials Science · Physics 2016-11-10 Thomas Jourdan , Gabriel Stoltz , Frédéric Legoll , Laurent Monasse

We perform three-dimensional simulations of homogeneous and inhomogeneous cosmologies via the coupling of a numerical relativity code for spacetime evolution and smoothed particle hydrodynamics (SPH) code. Evolution of a flat dust and…

General Relativity and Quantum Cosmology · Physics 2023-07-31 Spencer J. Magnall , Daniel J. Price , Paul D. Lasky , Hayley J. Macpherson

We describe a new approach for modeling the transport of high energy particles accelerated during flares from the acceleration region in the solar corona until their eventual thermalization in the flare footpoint. Our technique numerically…

Solar and Stellar Astrophysics · Physics 2020-10-14 Joel C. Allred , Meriem Alaoui , Adam F. Kowalski , Graham S. Kerr

We have studied the impact of cosmic-ray acceleration in SNR on the spectra of cosmic-ray nuclei in the Galaxy using a series expansion of the propagation equation, which allows us to use analytical solutions for part of the problem and an…

Astrophysics · Physics 2009-11-10 I. Buesching , A. Kopp , M. Pohl , R. Schlickeiser , C. Perrot , I. Grenier

Cosmic ray (CR) electrons reveal key insights into the non-thermal physics of the interstellar medium, galaxies, galaxy clusters, and active galactic nuclei by means of their inverse Compton {\gamma}-ray emission and synchrotron emission in…

High Energy Astrophysical Phenomena · Physics 2019-09-24 Georg Winner , Christoph Pfrommer , Philipp Girichidis , Rüdiger Pakmor

A Fokker Planck equation on fractal curves is obtained, starting from Chapmann-Kolmogorov equation on fractal curves. This is done using the recently developed calculus on fractals, which allows one to write differential equations on…

Mathematical Physics · Physics 2010-04-27 Seema E. Satin , Abhay Parvate , A. D. Gangal

A challenging requirement posed by next-generation observations is a firm theoretical grasp of the impact of baryons on structure formation. Cosmological hydrodynamic simulations modeling gas physics are vital in this regard. A high degree…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-05 J. D. Emberson , Nicholas Frontiere , Salman Habib , Katrin Heitmann , Patricia Larsen , Hal Finkel , Adrian Pope

The dissociation of CO2 molecules in plasmas is a subject of enormous importance for fundamental studies and the recent interest in carbon capture and carbon-neutral fuels. The vibrational excitation of the CO2 molecule plays an important…

Chemical Physics · Physics 2017-09-27 Paola Diomede , Mauritius C. M. van de Sanden , Savino Longo

We investigate the impact of cosmic rays (CRs) on galactic outflows from a multi-phase interstellar medium with solar neighbourhood conditions. The three-dimensional magneto-hydrodynamical simulations include CRs as a relativistic fluid in…

Astrophysics of Galaxies · Physics 2018-07-11 Philipp Girichidis , Thorsten Naab , Michał Hanasz , Stefanie Walch

Solar flares involve complex processes that are coupled and span a wide range of temporal, spatial, and energy scales. Modeling such processes self-consistently has been a challenge in the past. Here we present results from simulations that…

Solar and Stellar Astrophysics · Physics 2015-11-18 Fatima Rubio da Costa , Wei Liu , Vahe' Petrosian , Mats Carlsson

Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary to primary nuclei ratios (e.g., boron/carbon)…

Astrophysics · Physics 2009-11-07 I. V. Moskalenko , A. W. Strong , S. G. Mashnik , J. F. Ormes