A new method for analyzing line-tied kink modes in cylindrical geometry

Journal Article · Sat Jul 15 04:00:00 EDT 2006 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2219426· OSTI ID:20860138

Evstatiev, E G; Delzanno, G L; Finn, J M ^[1]

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1. T-15 Plasma Theory Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

A new method for studying linear stability of the m=1 (kink) mode in a cylinder with line-tied boundary conditions is presented. The method is applicable to both resistive and ideal MHD. It is based on expansion in one-dimensional eigenfunctions depending on the radius, satisfying boundary conditions on the cylindrical axis and radial wall. The boundary conditions at the end plates are satisfied by a sum of such radial eigenfunctions. The spectrum of possibly complex axial eigenvalues k is studied and is shown to consist of a continuum part and a discrete part in ideal MHD. Only the discrete part is used to give an approximation to the complete two-dimensional eigenfunction. The method is applied to a special equilibrium magnetic field with constant field line pitch. The role of the individual radial eigenfunctions is explained. It is shown that our method reproduces previously found values of the critical pitch (at marginal stability) for a plasma column in vacuum. The method also suggests important differences between ideal and resistive MHD.

• OSTI ID: 20860138
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 13; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
APPROXIMATIONS
BOUNDARY CONDITIONS
CYLINDRICAL CONFIGURATION
EIGENFUNCTIONS
EIGENVALUES
KINK INSTABILITY
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
PLASMA
PLASMA EXPANSION
STABILITY
WALL EFFECTS