On the generation of mean fields by small-scale electron magnetohydrodynamic turbulence

Lakhin, V. P.; Schep, T. J.

doi:10.1063/1.1645275

Cited by 3 publications

(1 citation statement)

References 27 publications

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“…25 However, he addresses the turbulence described within the model of electron magnetohydrodynamics, whereas we consider both the effects of electrons and ions.…”

Section: Introductionmentioning

confidence: 99%

Zonal flows generated by small-scale drift-Alfvén modes

et al. 2006

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The generation of zonal flows by small-scale drift-Alfvén (SSDA) modes is investigated. It is shown that these zonal flows can be generated by a monochromatic wave packet of SSDA modes propagating in the ion diamagnetic drift direction. The corresponding zonal-flow instability resembles a hydrodynamic one. Its growth rate depends on the spectrum purity of the wave packet; it decreases for relatively weak spectrum broadening and the instability turns into a resonant one, and eventually is suppressed, as the broadening increases. A general conclusion of this work is that the SSDA modes are less effective for driving zonal flows than standard drift modes.

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“…25 However, he addresses the turbulence described within the model of electron magnetohydrodynamics, whereas we consider both the effects of electrons and ions.…”

Section: Introductionmentioning

confidence: 99%

Zonal flows generated by small-scale drift-Alfvén modes

et al. 2006

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Theory and simulations of electron vortices generated by magnetic pushing

et al. 2013

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Vortex formation and propagation are observed in kinetic particle-in-cell (PIC) simulations of magnetic pushing in the plasma opening switch. These vortices are studied here within the electron-magnetohydrodynamic (EMHD) approximation using detailed analytical modeling. PIC simulations of these vortices have also been performed. Strong v×B forces in the vortices give rise to significant charge separation, which necessitates the use of the EMHD approximation in which ions are fixed and the electrons are treated as a fluid. A semi-analytic model of the vortex structure is derived, and then used as an initial condition for PIC simulations. Density-gradient-dependent vortex propagation is then examined using a series of PIC simulations. It is found that the vortex propagation speed is proportional to the Hall speed vHall≡cB0/4πneeLn. When ions are allowed to move, PIC simulations show that the electric field in the vortex can accelerate plasma ions, which leads to dissipation of the vortex. This electric field contributes to the separation of ion species that has been observed to occur in pulsed-power experiments with a plasma-opening switch.

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Asymptotic scalings of fluid, incompressible “electron-only” reconnection instabilities: Electron-magnetohydrodynamics tearing modes

Betar

Sarto

2023

Physics of Plasmas

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We perform a numerical study of the scaling laws of tearing modes in different parameter regimes of incompressible fluid electron magnetohydrodynamics, both in the small and large wavelength limits, as well as for the fastest growing mode that can be destabilized in a large aspect ratio current sheet. We discuss the relevance of these results, also for the interpretation of the “electron-only reconnection regime,” recently identified in spacecraft measures and in numerical simulations of solar wind turbulence. We restrict here to a single parameter study, in which we selectively consider only one non-ideal effect among electron inertia, perpendicular resistivity, and perpendicular electron viscosity, and we also consider the cases in which a proportionality exists between the parallel and the perpendicular dissipative coefficients. While some known theoretical results are thus confirmed, in other regimes and/or wavelength limits, corrections are proposed with respect to some theoretical estimates already available in the literature. In other cases, the scalings are provided for the first time. All numerical results are justified in terms of heuristic arguments based on the measurement of the scaling laws of some new microscopic scales associated with the gradients of the eigenfunctions. The alternative scalings we have found are consistent with this interpretation.

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On the generation of mean fields by small-scale electron magnetohydrodynamic turbulence

Cited by 3 publications

References 27 publications

Zonal flows generated by small-scale drift-Alfvén modes

Zonal flows generated by small-scale drift-Alfvén modes

Theory and simulations of electron vortices generated by magnetic pushing

Asymptotic scalings of fluid, incompressible “electron-only” reconnection instabilities: Electron-magnetohydrodynamics tearing modes

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