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Related papers: Onset of magnetic reconnection in a collisionless,…

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We study the time-dependent formation and evolution of a current sheet (CS) in a magnetized, collisionless, high-beta plasma using hybrid-kinetic particle-in-cell simulations. An initially tearing-stable Harris sheet is frozen into a…

High Energy Astrophysical Phenomena · Physics 2022-05-04 Himawan W. Winarto , Matthew W. Kunz

We investigate the linear tearing instability in weakly collisional plasmas using a non-ideal gyrotropic-MHD framework, uncovering a previously unknown scaling relation for the instability growth rate in high-$\beta$ environments. Even…

Plasma Physics · Physics 2025-10-09 Gabriel L. Ferreira-Santos , Grzegorz Kowal , Diego A. Falceta-Gonçalves

Modeling collisionless magnetic reconnection rate is an outstanding challenge in basic plasma physics research. While the seemingly universal rate of an order $\mathcal{O}(0.1)$ is often reported in the low-$\beta$ regime, it is not clear…

Solar and Stellar Astrophysics · Physics 2021-05-26 Xiaocan Li , Yi-Hsin Liu

We investigate the role of kinetic instabilities driven by a proton anisotropy on the onset of magnetic reconnection by means of 2-D hybrid simulations. The collisionless tearing of a current sheet is studied in the presence of a proton…

Space Physics · Physics 2015-06-12 Lorenzo Matteini , Simone Landi , Marco Velli , William H. Matthaeus

Plasmoid-driven magnetic reconnection in elongated current sheets is suspected to be an ubiquitous phenomenon in space and astrophysical plasmas, but the mechanisms driving its onset and dynamics are still debated. Deciphering the physical…

The nonlinear state of a high-beta collisionless plasma is investigated when an imposed linear shear amplifies or diminishes a uniform magnetic field, driving pressure anisotropies and hence firehose/mirror instabilities. The evolution of…

High Energy Astrophysical Phenomena · Physics 2016-04-20 S. Melville , A. A. Schekochihin , M. W. Kunz

Slow dynamical changes in magnetic-field strength and invariance of the particles' magnetic moments generate ubiquitous pressure anisotropies in weakly collisional, magnetized astrophysical plasmas. This renders them unstable to fast,…

Plasma Physics · Physics 2015-06-22 F. Rincon , A. A. Schekochihin , S. C. Cowley

The results of kinetic simulations of magnetic reconnection in Harris current sheets are analyzed. A range of guide fields is considered to study reconnection in plasmas characterized by different $\beta$ values, $\beta > m_e/m_i$. Both an…

Astrophysics · Physics 2009-04-28 P. Ricci , J. U. Brackbill , W. Daughton , G. Lapenta

We numerically study magnetic reconnection on different spatial scales and at different heights in the weakly ionized plasma of the low solar atmosphere (around $300-800$~km above the solar surface) within a reactive 2.5 D multi-fluid…

Solar and Stellar Astrophysics · Physics 2018-12-12 Lei Ni , Vyacheslav S. Lukin

Magnetic reconnection, breaking and reorganization of magnetic field topology, is a fundamental process for rapid release of magnetic energy into plasma particles that occurs pervasively throughout the universe. In most natural…

The plasma {\beta} (the ratio of the plasma pressure to the magnetic pressure) of a system can have a large effect on its dynamics as high {\beta} enhances the effects of pressure anisotropies. We investigate the effects of {\beta} in a…

Solar and Stellar Astrophysics · Physics 2015-05-28 K. M. Schoeffler , J. F. Drake , M. Swisdak

With the support of hybrid-kinetic simulations and analytic theory, we describe the nonlinear behaviour of long-wavelength non-propagating (NP) modes and fast magnetosonic waves in high-$\beta$ collisionless plasmas, with particular…

High Energy Astrophysical Phenomena · Physics 2023-04-05 Stephen Majeski , Matthew W. Kunz , Jonathan Squire

Event horizon-scale observations of low-luminosity black hole accretion flows favor magnetically arrested disks, characterized by dynamically important magnetic fields ($\beta\lesssim1$, where $\beta$ is the ratio of plasma thermal pressure…

High Energy Astrophysical Phenomena · Physics 2026-03-10 Vedant Dhruv , Lorenzo Sironi , Jordy Davelaar , Aaron Tran

In collisionless and weakly collisional plasmas, such as hot accretion flows onto compact objects, the magnetorotational instability (MRI) can differ significantly from the standard (collisional) MRI. In particular, pressure anisotropy with…

High Energy Astrophysical Phenomena · Physics 2018-02-14 Jonathan Squire , Eliot Quataert , Matthew W. Kunz

We investigate the inverse cascade of magnetic energy in decaying, collisionless plasmas with moderate to high-$\beta$ values via first-principles numerical simulations and analytical theory. We find that pressure-anisotropy-driven…

Plasma Physics · Physics 2025-10-03 Zhuo Liu , Muni Zhou , Nuno F. G. Loureiro

We conduct a multiparametric study of driven magnetic reconnection relevant to recent experiments on colliding magnetized laser produced plasmas using particle-in-cell simulations. Varying the background plasma density, plasma resistivity,…

Magnetized plasma interactions are ubiquitous in astrophysical and laboratory plasmas. Various physical effects have been shown to be important within colliding plasma flows influenced by opposing magnetic fields, however, experimental…

The relationship between a decaying strong turbulence and the mirror instability in a slowly expanding plasma is investigated using two-dimensional hybrid expanding box simulations. We impose an initial ambient magnetic field perpendicular…

Space Physics · Physics 2017-04-12 P. Hellinger , S. Landi , L. Matteini , A. Verdini , L. Franci

Results from a numerical study of fluctuation dynamo in a collisionless, weakly magnetized plasma are presented. The key difference between this dynamo and its magnetohydrodynamic (MHD) counterpart is the adiabatic production of…

High Energy Astrophysical Phenomena · Physics 2018-08-17 Denis A. St-Onge , Matthew W. Kunz

Results are presented of a first study of collisionless magnetic reconnection starting from a recently found exact nonlinear force-free Vlasov-Maxwell equilibrium. The initial state has a Harris sheet magnetic field profile in one direction…

Solar and Stellar Astrophysics · Physics 2016-03-23 Fiona Wilson , Thomas Neukirch , Michael Hesse , Michael G. Harrison , Craig R. Stark
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