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Title: Nonlinear Alfvén wave dynamics in plasmas

Nonlinear Alfvén wave dynamics is presented using Lagrangian fluid approach in a compressible collisional magnetized plasma. In the framework of two fluid dynamics, finite electron inertia is shown to serve as a dispersive effect acting against the convective nonlinearity. In a moving frame, the Alfvén wave can, therefore, form an arbitrarily strong amplitude solitary wave structure due to the balance between nonlinearity and dispersion. Weak amplitude Alfvén waves are shown to be governed by a modified KdV equation, which extends for finite dissipation to a mKdV-Burgers equation. These equations have well known solutions. Next, we have analyzed the fourth order nonlinear Alfvén wave system of equations both numerically and by approximation method. The results indicate a collapse of the density and magnetic field irrespective of the presence of dispersion. The wave magnetic field, however, appears to be less singular showing collapse only when the dispersive effects are negligible. These results may contribute to our understanding of the generation of strongly localized magnetic fields (and currents) in plasmas and are expected to be of special importance in the astrophysical context of magnetic star formation.
Authors:
;  [1] ;  [2]
  1. Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)
  2. Theoretical Physics, University of Bayreuth, D-95440 Bayreuth (Germany)
Publication Date:
OSTI Identifier:
22490006
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 7; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALFVEN WAVES; ASTROPHYSICS; DENSITY; ELECTRONS; FLUID MECHANICS; KORTEWEG-DE VRIES EQUATION; LAGRANGIAN FUNCTION; MAGNETIC FIELDS; MAGNETIC STARS; MATHEMATICAL SOLUTIONS; MOMENT OF INERTIA; NONLINEAR PROBLEMS; PLASMA