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The presence of magnetohydrodynamic (MHD) acceleration modes in pulsed plasma thrusters has been verified using the magnetic extension of Rankine-Hugoniot theory. However, the impact of initial conditions within the accelerator volume on…

Plasma Physics · Physics 2025-05-01 Ethan Horstman , Adrian Woodley , Thomas C. Underwood

Identifying generic physical mechanisms responsible for the generation of magnetic fields and turbulence in differentially rotating flows is fundamental to understand the dynamics of astrophysical objects such as accretion disks and stars.…

Astrophysics · Physics 2009-11-13 F. Rincon , G. I. Ogilvie , M. R. E. Proctor , C. Cossu

The onset of dynamo action is investigated within the context of a newly developed low Rossby, low magnetic Prandtl number, convection-driven dynamo model. This multiscale model represents an asymptotically exact form of an $\alpha^2$ mean…

Numerical solutions of the incompressible magnetohydrodynamic (MHD) equations are reported for the interior of a rotating, perfectly-conducting, rigid spherical shell that is insulator-coated on the inside. A previously-reported spectral…

Fluid Dynamics · Physics 2009-11-13 P. D. Mininni , D. C. Montgomery , L. Turner

According to the kinematic theory of nonhelical dynamo action the magnetic energy spectrum increases with wavenumber and peaks at the resistive cutoff wavenumber. It has previously been argued that even in the dynamical case the magnetic…

Astrophysics · Physics 2009-11-10 Nils Erland L. Haugen , Axel Brandenburg , Wolfgang Dobler

We study the dynamo threshold of a helical flow made of a mean (stationary) plus a fluctuating part. Two flow geometries are studied, either (i) solid body or (ii) smooth. Two well-known resonant dynamo conditions, elaborated for stationary…

Fluid Dynamics · Physics 2009-11-13 Marine Peyrot , Franck Plunian , Christiane Normand

This work provides a concrete implementation of E. Fermi's model of particle acceleration in magnetohydrodynamic (MHD) turbulence, connecting the rate of energization to the gradients of the velocity of magnetic field lines, which it…

High Energy Astrophysical Phenomena · Physics 2022-11-30 Martin Lemoine

We demonstrate that a magneto-convection simulation incorporating essential physical processes governing solar surface convection exhibits turbulent small-scale dynamo action. By presenting a derivation of the energy balance equation and…

Solar and Stellar Astrophysics · Physics 2010-04-23 Jonathan Pietarila Graham , Robert Cameron , Manfred Schuessler

The standard magnetohydrodynamic (MHD) description of the plasma in the hot, magnetized gas of the intra-cluster (ICM) medium is not adequate because it is weakly collisional. In such collisionless magnetized gas, the microscopic velocity…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 R. Santos-Lima , E. M. de Gouveia Dal Pino , A. Lazarian , G. Kowal , D. Falceta-Gonçalves

In this paper, we propose a new unified first order hyperbolic model of Newtonian continuum mechanics coupled with electro-dynamics. The model is able to describe the behavior of moving elasto-plastic dielectric solids as well as viscous…

Fluid Dynamics · Physics 2017-09-13 Michael Dumbser , Ilya Peshkov , Evgeniy Romenski , Olindo Zanotti

The transition from weak to strong turbulence when passing from large to small scales in magnetohydrodynamic (MHD) turbulence with guide field is a cornerstone of anisotropic turbulence theory. We present the first check of this transition,…

Solar and Stellar Astrophysics · Physics 2015-06-04 Andrea Verdini , Roland Grappin

A hypothesis for sunspot formation is the buoyant emergence of magnetic flux tubes created by the strong radial shear at the tachocline. In this scenario, the magnetic field has to exceed a threshold value before it becomes buoyant and…

Solar and Stellar Astrophysics · Physics 2011-10-25 G. Guerrero , P. Käpylä

Magnetic reconnection requires, at least locally, a non-ideal plasma response. In collisionless space and astrophysical plasmas, turbulence could permit this instead of the too rare binary collisions. We investigated the influence of…

Plasma Physics · Physics 2016-05-25 Fabien Widmer , Jörg Büchner , Nobumitsu Yokoi

In certain astrophysical systems the commonly employed ideal magnetohydrodynamics (MHD) approximation breaks down. Here, we introduce novel explicit and implicit numerical schemes of ohmic resistivity terms in the moving-mesh code AREPO. We…

Instrumentation and Methods for Astrophysics · Physics 2018-03-09 Federico Marinacci , Mark Vogelsberger , Rahul Kannan , Philip Mocz , Rüdiger Pakmor , Volker Springel

We give a short review of our recent works on the first-order quantum phase transitions in frustrated spin chains with orthogonal-dimer structure. When the ratio of the competing antiferromagnetic exchange couplings is varied, a first-order…

Strongly Correlated Electrons · Physics 2009-11-07 Akihisa Koga , Akira Kawaguchi , Kouichi Okunishi , Norio Kawakami

Planets and stars are able to generate coherent large-scale magnetic fields by helical convective motions in their interiors. This process, known as hydromagnetic dynamo, involves nonlinear interaction between the flow and magnetic field.…

Fluid Dynamics · Physics 2025-05-13 Anna Guseva , Ludovic Petitdemange , Steven M. Tobias

We study the stability of first-order dissipative spin-hydrodynamic frameworks. We considered two different first-order dissipative spin-hydrodynamic frameworks. The first one considers the spin chemical potential ($\omega^{\alpha\beta}$)…

Nuclear Theory · Physics 2023-04-12 Asaad Daher , Arpan Das , Radoslaw Ryblewski

We formulate the theory of first-order dissipative magnetohydrodynamics in an arbitrary hydrodynamic frame under the assumption of parity-invariance and discrete charge symmetry. We study the mode spectrum of Alfv\'en and magnetosonic waves…

High Energy Physics - Theory · Physics 2022-10-14 Jay Armas , Filippo Camilloni

The interplay between disorder and compressibility in Ising magnets is studied. Contrary to pure systems in which a weak compressibility drives the transition first order, we find from a renormalization group analysis that it has no effect…

Condensed Matter · Physics 2015-06-25 Yonathan Shapir , Serge Galam

A recent paper by Zaghoo et al. presents optical data at high-pressure and high-temperature and interprets the data as evidence for a first-order phase transition to metallic hydrogen during heating. Here we argue that the presented data…

Materials Science · Physics 2017-10-25 Alexander F. Goncharov , Zachary M. Geballe