On the possibility of electric-current sheets in dense formation

Low, B. C.
December 2007
Physics of Plasmas;Dec2007, Vol. 14 Issue 12, p122904
Academic Journal
This is a mathematical study of the formation of tangential discontinuities, or current sheets, in a magnetic field evolving in an electrically perfectly conducting fluid in response to deformation of its domain, an effect first treated by Hahm and Kulsrud [Phys. Fluids 28, 2412 (1985)]. Explicit examples are presented of three-dimensional, untwisted fields, anchored to the boundary, that cannot assume a force-free state in the absence of current sheets. The underlying physics of this process is as described by the Parker theory of spontaneous current sheets, namely, that for most continuous magnetic fields in complex three-dimensional geometry, there is an incompatibility between the preservation of field topology and point-by-point force balance to achieve equilibrium. This incompatibility is removed through discontinuous plasma displacements that produce magnetic tangential discontinuities. In contrast to the twisted magnetic fields central to the Parker theory, fixing the connectivity between the anchored magnetic footpoints alone is sufficient to lead to current-sheet formation in untwisted fields. This mode of sheet formation may produce spatially dense multitudes of sheets to heat a plasma throughout its macroscopic volume such as implied by several phenomena in the solar corona.


Related Articles

  • Plasma Flows in Crossed Magnetic and Electric Fields. Belikov, A. G. // Plasma Physics Reports;Sep2005, Vol. 31 Issue 9, p766 

    The effect of the magnitude and direction of an external electric field on the plasma flowing through a magnetic barrier is studied by numerically solving two-fluid MHD equations. The drift velocity of the plasma flow and the distribution of the flow electrons over transverse velocities are...

  • Nonlinear skin effect in a collisionless plasma. Froese, A. M.; Smolyakov, A. I.; Sydorenko, D. // Physics of Plasmas;Aug2009, Vol. 16 Issue 8, p080704 

    The skin effect in a warm collisionless plasma is studied via one-dimensional advective particle-in-cell simulations. It is found that the skin depth exhibits nonlinear behavior at low frequencies. A simple model describing the nonlinear behavior of the skin depth is proposed and shown to match...

  • Landau damping in relativistic plasmas with power-law distributions and applications to solar wind electrons. Podesta, J. J. // Physics of Plasmas;Dec2008, Vol. 15 Issue 12, p122902 

    The relativistic plasma dispersion relation is derived for Langmuir waves in a spatially homogeneous unmagnetized plasma in which the electrons have an isotropic power-law distribution in momentum space. The theory is applied to the study of Langmuir waves in the quiescent solar wind near the...

  • On the transition to drift turbulence in a magnetized plasma column. Burin, M. J.; Tynan, G. R.; Antar, G. Y.; Crocker, N. A.; Holland, C. // Physics of Plasmas;May2005, Vol. 12 Issue 5, p052320 

    Experimental results from a magnetized argon plasma column demonstrate a controlled transition to a turbulent state as the magnetic field (B) strength is increased. At lower B there is an onset of fluctuations in density and potential. These are shown to be due to drift waves that have been...

  • Characterization of core and edge turbulence in L- and enhanced Dα H-mode Alcator C-Mod plasmas. Basse, N. P.; Edlund, E. M.; Ernst, D. R.; Fiore, C. L.; Greenwald, M. J.; Hubbard, A. E.; Hughes, J. W.; Irby, J. H.; Lin, L.; Lin, Y.; Marmar, E. S.; Mossessian, D. A.; Porkolab, M.; Rice, J. E.; Snipes, J. A.; Stillerman, J. A.; Terry, J. L.; Wolfe, S. M.; Wukitch, S. J.; Zhurovich, K. // Physics of Plasmas;May2005, Vol. 12 Issue 5, p052512 

    The recently upgraded phase-contrast imaging (PCI) diagnostic is used to characterize the transition from the low (L) to the enhanced Dα (EDA) high (H) confinement mode in Alcator C-Mod [I. H. Hutchinson, R. Boivin, F. Bombarda et al., Phys. Plasmas 1, 1511 (1994)] plasmas. PCI yields...

  • Fluid theory of radial angular momentum flux of plasmas in an axisymmetric magnetic field. Wong, S. K.; Chan, V. S. // Physics of Plasmas;Nov2007, Vol. 14 Issue 11, p112505 

    The fluid equations of Mikhailovskii and Tsypin have been applied to the problem of radial transport of angular momentum of plasmas in an axisymmetric magnetic field with flux surfaces of arbitrary shape [P. J. Catto and A. N. Simakov, Phys. Plasmas 12, 012501 (2005)]. In this paper, compact...

  • Jets as accelerators of ultrahigh-energy cosmic ray particles. Trubnikov, B. A.; Vlasov, V. P. // Journal of Experimental & Theoretical Physics;Nov2008, Vol. 107 Issue 5, p769 

    The model of a cosmic jet that operates in the regimes of an MHD nozzle and a unipolar inductor is considered. It is shown that the “solid-body” rotation (according to Ferraro’s law) of helical magnetic field lines should lead to an acceleration of a small fraction of the...

  • Equilibrium evolution in oscillating-field current-drive experiments. McCollam, K. J.; Anderson, J. K.; Blair, A. P.; Craig, D.; Den Hartog, D. J.; Ebrahimi, F.; O'Connell, R.; Reusch, J. A.; Sarff, J. S.; Stephens, H. D.; Stone, D. R.; Brower, D. L.; Deng, B. H.; Ding, W. X. // Physics of Plasmas;Aug2010, Vol. 17 Issue 8, p082506 

    Oscillating-field current drive (OFCD) is a proposed method of steady-state toroidal plasma sustainment in which ac poloidal and toroidal loop voltages are applied to produce a dc plasma current. OFCD is added to standard, inductively sustained reversed-field pinch plasmas in the Madison...

  • Particle-in-cell simulations of ultra intense laser pulses propagating through overdense plasma for fast-ignitor and radiography applications. Lasinski, Barbara F.; Langdon, A. Bruce; Hatchett, Stephen P.; Key, Michael H.; Tabak, Max // Physics of Plasmas;May99, Vol. 6 Issue 5, p2041 

    Zohar (two-dimensions, particle-in-cell) [C. K. Birdsall and A. B. Langdon, Plasma Physics via Computer Simulation (McGraw-Hill, New York, 1985)] simulations of ultra intense laser beams boring into overdense plasmas whose parameters are guided by the fast-ignitor concept and radiography...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics