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Three-dimensional numerical simulations of magnetoacoustic wave propagation are performed in a sunspot atmosphere with a computational domain covering from the photosphere to the chromosphere. The wave source, with properties resembling the…

Solar and Stellar Astrophysics · Physics 2010-05-21 T. Felipe , E. Khomenko , M. Collados

The Lorentz force induced by the magnetic field in MHD flow introduces a fundamental difference from pure gas dynamics by facilitating the anisotropic propagation of small disturbances, thus the type of steady MHD equations depends on not…

Analysis of PDEs · Mathematics 2025-10-30 Shangkun Weng , Wengang Yang

We report analysis of sub-Alfv\'enic magnetohydrodynamic (MHD) perturbations in the low-\b{eta} radial-field solar wind using the Parker Solar Probe spacecraft data from 31 October to 12 November 2018. We calculate wave vectors using the…

Solar and Stellar Astrophysics · Physics 2022-01-05 S. Q. Zhao , Huirong Yan , Terry Z. Liu , Mingzhe Liu , Mijie Shi

Following the wellknown spacetime decomposition technique as applied to (d+1) dimensions we write down the equations of magnetohydrodynamics (MHD) in a spatially at generalised FRW universe. Assuming an equation of state for the background…

General Relativity and Quantum Cosmology · Physics 2009-09-28 D. Panigrahi , Ajanta Das , S. Chatterjee

We demonstrate that in highly magnetized pair plasmas, nonlinear Alfven waves with wave-number $k \leq k_0 = \omega_p^2 /(\delta \omega_B)$ ($\delta =( \delta B)/B_0$ are relative fluctuations of the magnetic field) experience powerful…

High Energy Astrophysical Phenomena · Physics 2026-05-05 Maxim Lyutikov

Alfv\'enic turbulence is an effective mechanism for particle acceleration in strongly magnetized, relativistic plasma. In this study, we investigate a scenario where turbulent plasma is influenced by a strong guide magnetic field, resulting…

Plasma Physics · Physics 2025-05-20 Cristian Vega , Stanislav Boldyrev , Vadim Roytershteyn

Crustal quakes of highly magnetized neutron stars can disrupt their magnetospheres, triggering energetic phenomena like X-ray and fast radio bursts (FRBs). Understanding plasma wave dynamics in these extreme environments is vital for…

High Energy Astrophysical Phenomena · Physics 2024-09-06 Jens F. Mahlmann , Miguel Á. Aloy , Xinyu Li

We study compressible MHD turbulence, which holds key to many astrophysical processes, including star formation and cosmic ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid we use wavelet…

Astrophysics of Galaxies · Physics 2015-05-18 Grzegorz Kowal , Alex Lazarian

This paper investigates the changes in spatial properties when magnetohydrodynamic (MHD) waves undergo resonant damping in the Alfv\'en continuum. The analysis is carried out for a 1D cylindrical pressure-less plasma with a straight…

Solar and Stellar Astrophysics · Physics 2020-09-18 M. Goossens , I. Arregui , R. Soler , T. Van Doorsselaere

The strong alignment of small-scale turbulent Alfv\'enic motions with the direction of the magnetic field that percolates the small-scale eddies and imprints the direction of the magnetic field is a property that follows from the MHD theory…

Astrophysics of Galaxies · Physics 2021-04-20 Ka Wai Ho , Alex Lazarian

An enhancement in high-frequency acoustic power is commonly observed in the solar photosphere and chromosphere surrounding magnetic active regions. We perform 3D linear forward wave modelling with a simple wavelet pulse acoustic source to…

Solar and Stellar Astrophysics · Physics 2015-06-23 Carlos Rijs , Hamed Moradi , Damien Przybylski , Paul S. Cally

First results of the inversion of Stokes I and V profiles from plage regions near disk center are presented. Both low and high spatial resolution spectra of FeI 6301.5 and FeI 6302.5 A obtained with the Advanced Stokes Polarimeter (ASP)…

Astrophysics · Physics 2009-10-30 L. R. Bellot Rubio , B. Ruiz Cobo , M. Collados

Diffuse striations in molecular clouds are preferentially aligned with local magnetic fields whereas dense filaments tend to be perpendicular to them. When and why this transition occurs remain uncertain. To explore the physics behind this…

Astrophysics of Galaxies · Physics 2016-10-05 Che-Yu Chen , Patrick K. King , Zhi-Yun Li

Magneto-hydrodynamic (MHD) Alfv\'en waves have been a focus of laboratory plasma physics and astrophysics for over half a century. Their unique nature makes them ideal energy transporters, and while the solar atmosphere provides…

Realistic numerical simulations, i.e., those that make minimal use of ad hoc modeling, are essential for understanding the complex turbulent dynamics of the interiors and atmospheres of the Sun and other stars and the basic mechanisms of…

Solar and Stellar Astrophysics · Physics 2015-07-30 Alan A. Wray , Khalil Bensassi , Irina N. Kitiashvili , Nagi N. Mansour , Alexander G. Kosovichev

The super simple Vlasov (ssV) code was developed to study instabilities, turbulence, and reconnection in weakly magnetized plasmas, such as the solar wind in the dissipation range and the edge of fusion plasmas. The ssV code overcomes the…

Rapid shear motion of magnetar crust can launch Alfv\'{e}n waves into the magnetosphere. The dissipation of the Alfv\'{e}n waves has been theorized to power the X-ray bursts characteristic of magnetars. However, the process by which…

High Energy Astrophysical Phenomena · Physics 2025-06-10 Dominic Bernardi , Yajie Yuan , Alexander Y. Chen

Rapid acceleration and burst maneuvers in underwater robots depend less on maintaining precise resonance and more on force--velocity phase alignment during thrust generation. In this work, we investigate constrained-layer damping (CLD) as a…

Robotics · Computer Science 2026-03-05 Qimin Feng , Orion A. Roberts , Qiang Zhong

In this paper, we report our detailed analysis of the new strong-coupling regime between Alfv\'en and fast modes in Poynting-dominated plasma turbulence, reported in our previous work Takamoto & Lazarian (2016), which is an important effect…

High Energy Astrophysical Phenomena · Physics 2017-10-18 Makoto Takamoto , Alexandre Lazarian

In solar physics, a severe numerical challenge for modern simulations is properly representing a transition region between the million-degree hot corona and a much cooler plasma of about 10000 K (e.g., the upper chromosphere or a…

Solar and Stellar Astrophysics · Physics 2021-04-07 Yu-Hao Zhou , Wen-Zhi Ruan , Chun Xia , Rony Keppens