Force balance in current sheets in collisionless plasma

In this paper, we derive a divergent form of the force balance equation for collisionless plasma in the quasineutrality approximation, in which the electric field and current density are excluded. For a stationary spatially one-dimensional current sheet with a constant normal component of the magnetic field and magnetized electrons, the general form of the force balance equation has been obtained for the first time in the form of a conservation law. An equation in this form is necessary for the correct formulation of boundary conditions when modeling asymmetric current sheets, as well as for the control of the stationarity of the numerical solution obtained in the model. Furthermore, the fulfillment of this equation is considered for two types of stationary configurations of a thin current sheet, which are obtained using a numerical model. The derived equation makes it possible to develop models of asymmetric current sheets, in particular current sheets on the magnetopause flanks in the magnetotail.

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Force balance in current sheets

10.5194/egusphere-egu2020-2210 ◽

2020 ◽

Author(s):

Olеg Mingalev ◽

Igor Mingalev

Keyword(s):

Balance Equation ◽

Force Balance ◽

Current Sheets ◽

Electron Pressure ◽

Equation Solving ◽

Pressure Anisotropy ◽

Correct Determination ◽

The Magnetic Field ◽

Force Balance Equation

<p>A new form of the proton force balance equation for the plasma consisting of collisionless protons and magnetized electrons is obtained. In the equation, the electric field is expressed through the magnetic field and the divergence of electron pressure tensor. The latter is reqiured for the correct determination of boundary conditions in models of current sheets to control the force balance in the models of that type. From this, a general form of the force balance equation in a one-dimensional current sheet is obtained, and effects of electron pressure anisotropy are considered. We reproduce realistic stationary configurations of current sheets using novel methods of numerical simulations and the Vlasov equation solving.&#160;</p>

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Nonlinear equilibrium structure of thin currents sheets: influence of electron pressure anisotropy

Nonlinear Processes in Geophysics ◽

10.5194/npg-11-579-2004 ◽

2004 ◽

Vol 11 (5/6) ◽

pp. 579-587 ◽

Cited By ~ 59

Author(s):

L. M. Zelenyi ◽

H. V. Malova ◽

V. Yu. Popov ◽

D. Delcourt ◽

A. S. Sharma

Keyword(s):

Magnetic Field ◽

Current Sheet ◽

Magnetic Energy ◽

Plasma Pressure ◽

Quasi Equilibrium ◽

Electrostatic Effects ◽

Current Sheets ◽

Thin Current Sheet ◽

Field Lines ◽

The Magnetic Field

Abstract. Thin current sheets represent important and puzzling sites of magnetic energy storage and subsequent fast release. Such structures are observed in planetary magnetospheres, solar atmosphere and are expected to be widespread in nature. The thin current sheet structure resembles a collapsing MHD solution with a plane singularity. Being potential sites of effective energy accumulation, these structures have received a good deal of attention during the last decade, especially after the launch of the multiprobe CLUSTER mission which is capable of resolving their 3D features. Many theoretical models of thin current sheet dynamics, including the well-known current sheet bifurcation, have been developed recently. A self-consistent 1D analytical model of thin current sheets in which the tension of the magnetic field lines is balanced by the ion inertia rather than by the plasma pressure gradients was developed earlier. The influence of the anisotropic electron population and of the corresponding electrostatic field that acts to restore quasi-neutrality of the plasma is taken into account. It is assumed that the electron motion is fluid-like in the direction perpendicular to the magnetic field and fast enough to support quasi-equilibrium Boltzmann distribution along the field lines. Electrostatic effects lead to an interesting feature of the current density profile inside the current sheet, i.e. a narrow sharp peak of electron current in the very center of the sheet due to fast curvature drift of the particles in this region. The corresponding magnetic field profile becomes much steeper near the neutral plane although the total cross-tail current is in all cases dominated by the ion contribution. The dependence of electrostatic effects on the ion to electron temperature ratio, the curvature of the magnetic field lines, and the average electron magnetic moment is also analyzed. The implications of these effects on the fine structure of thin current sheets and their potential impact on substorm dynamics are presented.

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Experimental test of the radial force balance equation in the compact helical system

Physics of Plasmas ◽

10.1063/1.1331097 ◽

2001 ◽

Vol 8 (1) ◽

pp. 1-4 ◽

Cited By ~ 17

Author(s):

K. Ida ◽

A. Fujisawa ◽

H. Iguchi ◽

Y. Yoshimura ◽

T. Minami ◽

...

Keyword(s):

Experimental Test ◽

Balance Equation ◽

Radial Force ◽

Force Balance ◽

Force Balance Equation

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Impurity Resistivity under Thermalized Condition

International Journal of Modern Physics B ◽

10.1142/s0217979292000566 ◽

1992 ◽

Vol 06 (07) ◽

pp. 1079-1098 ◽

Cited By ~ 1

Author(s):

C.S. Ting ◽

L.Y. Chen

Keyword(s):

Relaxation Time ◽

Balance Equation ◽

Center Of Mass ◽

Charge Carriers ◽

Force Balance ◽

Electron Interaction ◽

Time Approximation ◽

Relaxation Time Approximation ◽

Scattering Time ◽

Force Balance Equation

The standard impurity resistivity based upon the force-balance equation is derived with use of the method of closed-time-path Green’s functions. In this the effects from both the noncommutability of the center of mass fluctuations at different times and the exact noncannonical commutation relations between the coordinates and momentum of relative electrons are considered. In the presence of a short momentum-conserving inelastic scattering time due to electron-electron interaction, fast thermalization among charge carriers can be achieved. Under this condition, the (thermalized) impurity resistivity will have different form than the standard impurity resistivity and it is practically given by the lowest order electron-impurity term in the force balance equation. We also demonstrate that this conclusion is consistent with results based upon the Boltzmann equation in a relaxation time approximation.

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A model of one-dimensional current sheet with parallel currents and normal component of magnetic field

Physics of Plasmas ◽

10.1063/1.3552141 ◽

2011 ◽

Vol 18 (2) ◽

pp. 022104 ◽

Cited By ~ 42

Author(s):

A. V. Artemyev

Keyword(s):

Magnetic Field ◽

Current Sheet ◽

Normal Component ◽

One Dimensional

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Consistent derivation of impurity resistivity from the force-balance equation

Physical Review B ◽

10.1103/physrevb.42.1129 ◽

1990 ◽

Vol 42 (2) ◽

pp. 1129-1141 ◽

Cited By ~ 7

Author(s):

L. Y. Chen ◽

C. S. Ting ◽

N. J. M. Horing

Keyword(s):

Balance Equation ◽

Force Balance ◽

Force Balance Equation

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Dynamic Mitigation of Tearing Mode Instability in Current Sheet in Collisionless Plasma

10.21203/rs.3.rs-242784/v1 ◽

2021 ◽

Author(s):

Yan-Jun Gu ◽

Shigeo Kawata ◽

Sergei Bulanov

Keyword(s):

Current Sheet ◽

Small Amplitude ◽

Collisionless Plasma ◽

Electron Current ◽

Tearing Mode ◽

Mode Instability ◽

Feed Forward Control ◽

Instability Growth ◽

Field Lines ◽

The Magnetic Field

Abstract Dynamic mitigation for the tearing mode instability in the current sheet in collisionless plasma is demonstrated by applying a wobbling electron current beam. The initial small amplitude modulations imposed on the current sheet induce the electric current filamentation and the reconnection of the magnetic field lines. When the wobbling or oscillation motion is added from the electron beam having a form of a thin layer moving along the current sheet, the perturbation phase is mixed and consequently the instability growth is saturated remarkably, like in the case of the feed-forward control.

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