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Large scale dynamos produce small scale current helicity as a waste product that quenches the large scale dynamo process (alpha effect). This quenching can be catastrophic (i.e.intensify with magnetic Reynolds number) unless one has fluxes…

Astrophysics · Physics 2007-05-23 Kandaswamy Subramanian , Axel Brandenburg

Magnetic field amplification in astrophysics ultimately requires an understanding of magnetohydrodynamic turbulence. Kinetic helicity has long been known to be important for large scale field growth in forced MHD turbulence, and has been…

Astrophysics · Physics 2009-11-07 Jason Maron , Eric G. Blackman

In this paper, we are concerned with the energy and magnetic helicity conservation of weak solutions for both the electron and Hall magnetohydrodynamic equations. Various sufficient criteria to ensure the energy and magnetic helicity…

Analysis of PDEs · Mathematics 2023-03-23 Yanqing Wang , Jing Yang , Yulin Ye

Quantum simulation is a prominent application of quantum computers. While there is extensive previous work on simulating finite-dimensional systems, less is known about quantum algorithms for real-space dynamics. We conduct a systematic…

Quantum Physics · Physics 2022-11-23 Andrew M. Childs , Jiaqi Leng , Tongyang Li , Jin-Peng Liu , Chenyi Zhang

In turbulence, for neutral or conducting fluids, a large ratio of scales is excited because of the possible occurrence of inverse cascades to large, global scales together with direct cascades to small, dissipative scales, as observed in…

Fluid Dynamics · Physics 2020-02-03 Annick Pouquet , Julia E. Stawarz , Duane Rosenberg

Magnetic helicity is a quantity that underpins many theories of magnetic relaxation in electrically conducting fluids, both laminar and turbulent. Although much theoretical effort has been expended on magnetic fields that are everywhere…

Plasma Physics · Physics 2025-04-18 Sauli Lindberg , David MacTaggart

The paper address the effects of magnetic helicity conservation in a non-linear nonaxisymmetric mean-field solar dynamo model. We study the evolution of the shallow non-axisymmetric magnetic field perturbation with the strength about 10G in…

Solar and Stellar Astrophysics · Physics 2016-01-21 V. V. Pipin

The elliptical instability can take place in planetary cores and stars elliptically deformed by gravitational effects, where it generates large-scale three-dimensional flows assumed to be dynamo capable. In this work, we present the first…

Classical Physics · Physics 2013-09-10 David Cébron , Michael Le Bars , Pierre Maubert , Patrice Le Gal

Using direct numerical simulations we demonstrate that magnetic helicity exhibits a bidirectional turbulent cascade at high but finite magnetic Reynolds numbers. Despite the injection of positive magnetic helicity in the flow, we observe…

Fluid Dynamics · Physics 2017-05-23 Moritz Linkmann , Vassilios Dallas

We review a family of local algorithms that permit the simulation of charged particles with purely local dynamics. Molecular dynamics formulations lead to discretizations similar to those of ``particle in cell'' methods in plasma physics.…

Statistical Mechanics · Physics 2009-11-10 A. C. Maggs , J. Rottler

Magnetized turbulence is ubiquitous in many astrophysical and terrestrial plasmas but no universal theory exists. Even the detailed energy dynamics in magnetohydrodynamic (MHD) turbulence are still not well understood. We present a suite of…

Astrophysics of Galaxies · Physics 2023-02-06 Philipp Grete , Brian W. O'Shea , Kris Beckwith

(abridged) Aims: Three-dimensional numerical simulations of penetrative compressible convection with uniform horizontal shear are used to study dynamo action and the generation of large-scale magnetic fields. Methods: We consider cases…

Astrophysics · Physics 2008-11-10 P. J. Käpylä , M. J. Korpi , A. Brandenburg

We numerically examine dynamo action generated by a flow of an electrically conducting fluid in a precessing cylindrical cavity. We compare a simplified kinematic approach based on the solution of the magnetic induction equation with a…

Fluid Dynamics · Physics 2025-04-07 André Giesecke , Mike Wilbert , Ján Šimkanin , Rainer Grauer , Frank Stefani

Based on a decomposition of the magnetic field into potential and nonpotential components, magnetic energy and relative helicity can both also be decomposed into two quantities: potential and free energies, and volume-threading and…

Solar and Stellar Astrophysics · Physics 2020-04-15 Luis Linan , Étienne Pariat , Guillaume Aulanier , Kostas Moraitis , Gherardo Valori

Astrophysical objects with negligible resistivity are often threaded by large scale magnetic fields. The generation of these fields is somewhat mysterious, since a magnetic field in a perfectly conducting fluid cannot change the flux…

Astrophysics · Physics 2007-05-23 E. T. Vishniac , A. Lazarian , J. Cho

The $\Lambda$ effect describes a rotation-induced non-diffusive contribution to the Reynolds stress. It is commonly held responsible for maintaining the observed differential rotation of the Sun and other late-type stars. Here the…

Solar and Stellar Astrophysics · Physics 2020-02-18 Petri J. Käpylä

We search for observational signatures of magnetic helicity in data from all-sky radio polarization surveys of the Milky Way Galaxy. Such a detection would help confirm the dynamo origin of the field and may provide new observational…

Astrophysics of Galaxies · Physics 2020-10-14 J. L. West , R. N. Henriksen , K. Ferrière , A. Woodfinden , T. Jaffe , B. M. Gaensler , J. A. Irwin

This paper describes a numerical scheme for multi-fluid hydrodynamics in the limit of small mass densities of the charged particles. The inertia of the charged particles can then be neglected, which makes it possible to write an evolution…

Astrophysics · Physics 2009-11-10 S. A. E. G. Falle

The small-scale magnetic helicity produced as a by-product of the large-scale dynamo is believed to play a major role in dynamo saturation. In a mean-field model the generation of small-scale magnetic helicity can be modelled by using the…

Solar and Stellar Astrophysics · Physics 2010-11-30 Piyali Chatterjee , Axel Brandenburg , Gustavo Guerrero

Charged systems interacting via Coulomb forces can be efficiently simulated by introducing a local, diffusing degree of freedom for the electric field. This paper formulates the continuum electrodynamic equations corresponding to the…

Statistical Mechanics · Physics 2009-11-07 A. C. Maggs