Collisionless distribution function for the relativistic force-free Harris sheet

Stark, Craig R.; Neukirch, T.

doi:10.1063/1.3677268

Cited by 13 publications

(15 citation statements)

References 42 publications

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“…In contrast to the models described above, in this case the force balance is provided by the non-zero value of the shear magnetic field B y instead of the plasma pressure gradient. Subsequently, this model has been generalised for nonMaxwellian distribution functions of charged particles 48 , and relativistic plasmas 44 . Kinetic models of a force-free CS with a periodic transverse structure have also recently been developed 1 .…”

Section: Introductionmentioning

confidence: 99%

Kinetic model of force-free current sheets with non-uniform temperature

2015

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go.warwick.ac.uk/lib-publicationsOriginal citation: Kolotkov, D. Y., Vasko, I. Y. and Nakariakov, V. M.. (2015) Kinetic model of force-free current sheets with non-uniform temperature. Physics of Plasmas, 22 (11). 112902. Permanent WRAP URL:http://wrap.warwick.ac.uk/78634 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. The kinetic model of a one-dimensional force-free current sheet (CS) developed recently by M. Harrison and T. Neukirch (Phys. Rev. Lett., vol. 6, 2009) predicts uniform distributions of the plasma temperature and density across the CS. However, in realistic physical systems inhomogeneities of these plasma parameters may arise quite naturally due to the boundary conditions or local plasma heating. Moreover, as the CS spatial scale becomes larger than the characteristic kinetic scales (the regime often referred to as the MHD limit) it should be possible to set arbitrary density and temperature profiles. Thus, an advanced model has to allow for inhomogeneities of the macroscopic plasma parameters across the CS, to be consistent with the MHD limit. In this paper we generalise the kinetic model of a force-free current sheet, taking into account the inhomogeneity of the density and temperature across the CS. In the developed model the density may either be enhanced or depleted in the CS central region. The temperature profile is prescribed by the density profile, keeping the plasma pressure uniform across the CS. All macroscopic parameters, as well as the distribution functions for the protons and electrons, are determined analytically. Applications of the developed model to current sheets observed in space plasmas are discussed.

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Section: Introductionmentioning

confidence: 99%

Kinetic model of force-free current sheets with non-uniform temperature

2015

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“…The non-uniqueness of the 'inverse' approach was shown by Wilson and Neukirch [33] who showed that the P zz given in equation (33) can be obtained with distribution functions that have a different dependence on the Hamiltonian H s than in equation (34), but the same dependence on the canonical momenta. It was also shown in [40] how the forcefree Harris sheet distribution function (34) can be generalised to the relativistic regime.…”

Section: [3])mentioning

confidence: 99%

Collisionless current sheet equilibria

Neukirch

Wilson

Allanson

2017

Plasma Phys. Control. Fusion

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Current sheets are important for the structure and dynamics of many plasma systems. In space and astrophysical plasmas they play a crucial role in activity processes, for example by facilitating the release of magnetic energy via processes such as magnetic reconnection. In this contribution we will focus on collisionless plasma systems. A sensible first step in any investigation of physical processes involving current sheets is to find appropriate equilibrium solutions. The theory of collisionless plasma equilibria is well established, but over the past few years there has been a renewed interest in finding equilibrium distribution functions for collisionless current sheets with particular properties, for example for cases where the current density is parallel to the magnetic field (force-free current sheets). This interest is due to a combination of scientific curiosity and potential applications to space and astrophysical plasmas. In this paper we will give an overview of some of the recent developments, discuss their potential applications and address a number of open questions.

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“…It is the v -dependence of A ⋆ [Eq. (8)] that produces the singularity. In order to regularize the singularity v in (8) can be replaced by an antisymmetric function g(z) with z = v /v 0 , where v 0 is some constant velocity [30,31,33].…”

Section: Drift Kinetic Theorymentioning

confidence: 99%

“…Since solving self consistently the kinetic equations is tough particularly in complicated geometries the majority of kinetic equilibrium solutions are restricted to one dimensional configurations in plane geometry, e.g. [1]- [8]. Of particular interest are equilibria with sheared toroidal and poloidal flows which play a role in the transition to improved confinement regimes in tokamaks and stellarators, though understanding the physics of this transition remains incomplete.…”

Section: Introductionmentioning

confidence: 99%

Vlasov versus reduced kinetic theories for helically symmetric equilibria

Tasso

Throumoulopoulos

2013

Physics of Plasmas

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A new constant of motion for helically symmetric equilibria in the vicinity of the magnetic axis is obtained in the framework of Vlasov theory. In view of this constant of motion the Vlasov theory is compared with drift kinetic and gyrokinetic theories near axis. It turns out that as in the case of axisymmetric equilibria [H. Tasso and G. N. Throumoulopoulos, Phys. Plasmas 18, 064507 (2011)] the Vlasov current density thereon can differ appreciably from the drift kinetic and gyrokinetic current densities. This indicates some limitation on the implications of reduced kinetic theories, in particular as concerns the physics of energetic particles in the central region of magnetically confined plasmas.

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Collisionless distribution function for the relativistic force-free Harris sheet

Cited by 13 publications

References 42 publications

Kinetic model of force-free current sheets with non-uniform temperature

Kinetic model of force-free current sheets with non-uniform temperature

Collisionless current sheet equilibria

Vlasov versus reduced kinetic theories for helically symmetric equilibria

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