Helicity-Flux-Driven Alpha Effect in Laboratory and Astrophysical Plasmas

Abstract

The constraint imposed by magnetic helicity conservation on the alpha effect is considered for both magnetically and flow dominated self-organizing plasmas. Direct numerical simulations are presented for a dominant contribution to the alpha effect, which can be cast in the functional form of a total divergence of an averaged helicity flux, called the helicity-flux-driven alpha ( H$\alpha$) effect. Direct numerical simulations of the H$\alpha$ effect are prese nted for two examples---the magnetically dominated toroidal plasma unstable to tearing modes, and the flow-dominated accretion disk.

arXiv commentAccepted for publication PRL on Feb. 20 2014 - 4 pages (4 figures)

References in corpus (11)

• Sustained Magnetorotational Turbulence in Local Simulations of Stratified Disks with Zero Net Magnetic Flux
• Magnetic Helicity Conservation and Astrophysical Dynamos
• Constraints on the magnitude of alpha in dynamo theory
• Resistivity-driven State Changes in Vertically Stratified Accretion Disks
• Galactic dynamos supported by magnetic helicity fluxes
• On Self-Sustained Dynamo Cycles in Accretion Discs
• Nonlinear current helicity fluxes in turbulent dynamos and alpha quenching
• Turbulent dynamo with advective magnetic helicity flux
• Hyperdiffusion as a Mechanism for Solar Coronal Heating
• Saturation of Magnetorotational Instability through Magnetic Field Generation
• Comparisons and Connections between Mean Field Dynamo Theory and Accretion Disc Theory

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