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Related papers: Magnetic Helicity Tensor for an Anisotropic Turbul…

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It has been proposed recently by Loureiro & Boldyrev [Phys. Rev. Lett. 118, 245101 (2017)] and Mallet et al. [Mon. Not. R. Astron. Soc. 468, 4862 (2017)] that strongly anisotropic current sheets formed in the inertial range of…

Plasma Physics · Physics 2018-09-25 Justin Walker , Stanislav Boldyrev , Nuno Loureiro

On the framework of relativistic force-free magnetohydrodynamic (MHD) turbulence, we explore the fundamental properties of strong and weak turbulent cascades using high-resolution numerical simulations in the presence of a uniform…

High Energy Astrophysical Phenomena · Physics 2026-01-14 Na-Na Gao , Jian-Fu Zhang , Jungyeon Cho

In the paper we study the helicity density patterns which can result from the emerging bipolar regions. Using the relevant dynamo model and the magnetic helicity conservation law we find that the helicity density pattern around the bipolar…

Solar and Stellar Astrophysics · Physics 2021-02-17 V. V. Pipin

We determine the magnetic helicity, along with the magnetic energy, at high latitudes using data from the Ulysses mission. The data set spans the time period from 1993 to 1996. The basic assumption of the analysis is that the solar wind is…

Solar and Stellar Astrophysics · Physics 2015-03-17 Axel Brandenburg , Kandaswamy Subramanian , André Balogh , Melvyn L. Goldstein

In weakly collisional extragalactic plasmas such as the intracluster medium, viscous stress and the rate of change of the magnetic-field strength are proportional to the local pressure anisotropy, so subject to constraints imposed by the…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-26 Federico Mogavero , Alexander A. Schekochihin

Motivated by recent observations of distinct parallel and perpendicular signatures in magnetic helicity measurements segregated by wave period and angle between the local magnetic field and the solar wind velocity, this paper undertakes a…

Plasma Physics · Physics 2015-06-19 Kristopher G. Klein , Gregory G. Howes , Jason M. TenBarge , John J. Podesta

Using direct numerical simulations of three-dimensional magnetohydrodynamic (MHD) turbulence the spatio-temporal behavior of magnetic field fluctuations is analyzed. Cases with relatively small, medium and large values of a mean background…

Plasma Physics · Physics 2016-12-21 R. Lugones , P. Dmitruk , P. D. Mininni , M. Wan , W. H. Matthaeus

The measure of the third-order structure function, Y, is employed in the solar wind to compute the cascade rate of turbulence. In the absence of a mean field B0=0, Y is expected to be isotropic (radial) and independent of the direction of…

Solar and Stellar Astrophysics · Physics 2015-05-27 Andrea Verdini , Roland Grappin , Petr Hellinger , Simone Landi , Wolf-Christian Müller

Solar wind turbulence is often perceived as weakly compressible and the density fluctuations remain poorly understood both theoretically and observationally. Compressible magnetohydrodynamic simulations provide useful insights into the…

Space Physics · Physics 2023-04-12 Senbei Du , Hui Li , Zhaoming Gan , Xiangrong Fu

Roles of turbulence in the context of magnetic reconnection are investigated with special emphasis on the mutual interaction between flow (large-scale inhomogeneous structure) and turbulence. In order to evaluate the effective transport due…

Solar and Stellar Astrophysics · Physics 2015-05-28 Nobumitsu Yokoi , Masahiro Hoshino

Direct measurements of three-dimensional magnetic fields in the interstellar medium (ISM) are not achievable. However, the anisotropic nature of magnetohydrodynamic (MHD) turbulence provides a novel way of tracing the magnetic fields.…

Astrophysics of Galaxies · Physics 2021-07-14 Yue Hu , A. Lazarian , Siyao Xu

We present a quantitative estimate of the anisotropic power and scaling of magnetic field fluctuations in inertial range magnetohydrodynamic turbulence, using a novel wavelet technique applied to spacecraft measurements in the solar wind.…

Plasma Physics · Physics 2009-11-13 T. S. Horbury , M. A. Forman , S. Oughton

Magnetic helicity is conserved under ideal magnetohydrodynamics (MHD) and quasi-conserved even under a resistive process. The standard definition for magnetic helicity cannot be applied directly to an open magnetic field in a volume,…

Solar and Stellar Astrophysics · Physics 2020-05-27 Kai E. Yang , Michael S. Wheatland , Stuart A. Gilchrist

Plasma velocity and magnetic field measurements from the Voyager 2 mission are used to study solar wind turbulence in the slow solar wind at two different heliocentric distances, 5 and 29 astronomical units, sufficiently far apart to…

Solar and Stellar Astrophysics · Physics 2016-01-20 M. Iovieno , L. Gallana , F. Fraternale , J. D. Richardson , M. Opher , D. Tordella

We investigate hydromagnetic turbulence of primordial magnetic fields using magnetohydrodynamics (MHD) in an expanding universe. We present the basic, covariant MHD equations, find solutions for MHD waves in the early universe, and…

Astrophysics · Physics 2014-10-13 Axel Brandenburg , Kari Enqvist , Poul Olesen

It is currently believed that the turbulent fluctuations pervade the outermost heliosphere. Turbulence, magnetic reconnection, and their link may be responsible for magnetic energy conversion in these regions. The governing mechanisms of…

Magnetic field fluctuations in MHD turbulence can be viewed as current sheets that are progressively more anisotropic at smaller scales. As suggested by Loureiro & Boldyrev (2017) and Mallet et al (2017), below a certain critical thickness…

Plasma Physics · Physics 2017-08-09 Stanislav Boldyrev , Nuno F. Loureiro

We demonstrate that the inclusion of the helicity flux in the magnetic helicity balance in the nonlinear stage of galactic dynamo action results in a radical change in the magnetic field dynamics. The equilibrium value of the large-scale…

Astrophysics · Physics 2007-05-23 N. Kleeorin , D. Moss , I. Rogachevskii , D. Sokoloff

We investigate the relation between turbulence and magnetic field switchbacks in the inner heliosphere below 0.5 AU in a distance and scale dependent manner. The analysis is performed by studying the evolution of the magnetic field vector…

Solar and Stellar Astrophysics · Physics 2023-12-29 A. Larosa , C. H. K Chen , J. R. McIntyre , V. K. Jagarlamudi

Recent analysis of the helioseismic observations indicate that the previously observed surface torsional oscillations extend significantly downwards into the solar convection zone. In an attempt to understand these oscillations, we study…

Astrophysics · Physics 2007-05-23 Eurico Covas , Reza Tavakol , David Moss , Andrew Tworkowski