Open AccessCharacteristics of magnetohydrodynamic waves in Harris‐type current sheet with guide magnetic field B y
Author(s) -
Lee K.W.,
Hau L.N.
Publication year - 2008
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2008ja013459
Subject(s) - physics , magnetohydrodynamics , magnetic field , magnetohydrodynamic drive , alfvén wave , singularity , current sheet , field (mathematics) , gravitational singularity , type (biology) , classical mechanics , mathematical analysis , quantum mechanics , mathematics , biology , ecology , pure mathematics
An overview is presented of the characteristics of hydromagnetic waves propagating in Harris‐type current sheet with magnetic field of B x ( z ) and an embedded guide B y component based on the ideal magnetohydrodynamic (MHD) model. The wave equations are expressed in the ( k ∥ , k ⊥ , z ) coordinates, and singularities are identified for general cases of k y ≠ 0 and B y ≠ 0, where k ∥ and k ⊥ are the components of the wave vector parallel and perpendicular to the local magnetic field, respectively, and the inhomogeneity is in the z direction. The presence of B y may lead to the rotation of the magnetic field relative to the wave vector so that a singular layer with k ⊥ = 0 surrounded by a neighboring region of k ⊥ ≠ 0 may exist. This result is in contrast with the case of B y = 0 for which Alfvén or field‐line resonance associated with the mathematical singularity tends to occur for k ⊥ ≠ 0 and ω = k ∥ C A , where C A is the Alfvén speed. The possibility for MHD waves with frequency of ω = k ∥ C A to propagate through the inhomogeneous layer with B y ≠ 0 is analyzed, and numerical solutions for discrete eigenmodes with various free parameter values are presented.