Hall effect on tearing mode instabilities in tokamak

Zhang, Wei; W., Z.; Wang, S.

doi:10.1063/1.5004430

Cited by 45 publications

(36 citation statements)

References 27 publications

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“…These can include astrophysical plasmas, e.g., in non-relativistic magnetized jets [38] and disks [39], as well as laboratory plasmas, e.g. in magnetic confinement devices if the Hall term in Ohm's law is not negligible [40], and possibly in turbulent dynamo experiments induced by laser-plasma interactions [41,42].…”

Section: Discussionmentioning

confidence: 99%

Evidence of a "current-mediated" turbulent regime in space and astrophysical plasmas

Franci¹,

Sarto²,

Papini³

et al. 2020

Preprint

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How the turbulent energy cascade develops below the magnetohydrodynamic scales in space and astrophysical plasmas is a major open question. Here, we measure the power spectrum of magnetic fluctuations in Parker Solar Probe's observations close to the Sun and in state-of-the-art numerical simulations of plasma turbulence. Both reveal a power-law behavior with a slope compatible with −11/3 at scales smaller than the ion characteristic scales, steeper than what is typically observed in the solar wind and in the Earth's magnetosheath. We explain such behavior by developing a simple two-fluid model which does not require any kinetic processes nor electron-inertia effects. This is characterized by a significant contribution of the ion kinetic energy to the total turbulent energy cascade at sub-ion scales, although the dynamics is driven by the magnetic field through the current density. We expect that this regime may be relevant for a broad class of low-beta plasmas, e.g. the solar corona, non-relativistic magnetized jets and disks, and laboratory plasmas.

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Section: Discussionmentioning

confidence: 99%

Evidence of a "current-mediated" turbulent regime in space and astrophysical plasmas

Franci¹,

Sarto²,

Papini³

et al. 2020

Preprint

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“…The Hall effect has long been recognized as possibly a significant modification of canonical magnetohydrodynamics reconnection models (Birn & Priest ). The modification can increase growth rates of the tearing instability (Zhang et al ). However, the above computations show that the Hall effect alone can produce current sheets and catalyze resistive release of magnetic energy.…”

Section: Discussionmentioning

confidence: 99%

Stability of a force‐free Hall equilibrium and release of magnetic energy

Kitchatinov

2019

Astron Nachr

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Conservation of magnetic helicity by the Hall drift does not prevent Hall instability of helical fields. This conclusion follows from stability analysis of a force‐free spatially periodic Hall equilibrium. The growth rates of the instability scale as σ ∝ B3/4η1/4 with the field strength B and magnetic diffusivity η and can be large compared to the rate of resistive decay of the background field. The instability deviates the magnetic field from the force‐free configuration. The unstable eigenmodes include a fine spatial structure that evolves into current sheets at the nonlinear stage of the instability. The instability catalyzes the resistive release of magnetic energy. The energy is released in a sequence of spikes, every spike emits several percent of the total energy. A numerically defined scaling for the energy released in a single spike permits an extrapolation to astrophysically relevant values of the Hall number. The instability can be relevant to magnetic energy release in a neutron star crust and, possibly, in stellar coronae.

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“…Since minimizing the computational demand is a primary concern of an implicit time-advancing scheme, many existing programs employed the explicit scheme instead and achieved results with limited accuracy. For instance, the CLT code is a recently developed explicit solver for the simulation of MHD instabilities in toroidal devices [13,20], which has proven reliable under a wide range of practical conditions. However, the explicit difference scheme becomes a signi cant constraint in the long-term simulation.…”

Section: Introductionmentioning

confidence: 99%

A fully implicit parallel solver for MHD instabilities in a tokamak

Yao

Jiang

et al. 2022

Preprint

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Aiming at the long-term and high-precision simulation of the magnetohydrodynamic (MHD) instabilities in the tokamak model, we developed a parallelized solver based on a fully implicit difference scheme. A 4th-order precision difference scheme and the Newton-Krylov method are employed in the proposed solver for both the flow and the electromagnetic field. To achieve high parallel efficiency, we adopt a strategy based on the spatial domain decomposition to partition the large Jacobian matrices in the iteration, and a buffer area based on the grid density is utilized to minimize the memory and time consumption. The accuracy of the methodology is verified, and the numerical results are validated by comparison with recognized results. The numerical results of the tearing mode instability in the tokamak model have demonstrated the precision and reliability of the algorithm, and the high parallel efficiency has been proven by the scalability test on the platform with up to 1280 threads, showing significant potential in the large-scale simulation of MHD problems.

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Hall effect on tearing mode instabilities in tokamak

Cited by 45 publications

References 27 publications

Evidence of a "current-mediated" turbulent regime in space and astrophysical plasmas

Evidence of a "current-mediated" turbulent regime in space and astrophysical plasmas

Stability of a force‐free Hall equilibrium and release of magnetic energy

A fully implicit parallel solver for MHD instabilities in a tokamak

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