Neoclassical dissipation and resistive wall modes in tokamaks

Journal Article · Wed Dec 01 04:00:00 EST 2004 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.1806475· OSTI ID:20643929

Shaing, K C ^[1]

---

1. Engineering Physics Department, University of Wisconsin, Madison, Wisconsin 53706 (United States)

It is shown that the critical toroidal plasma flow speed that is required to stabilize the resistive wall mode in tokamaks is reduced by a factor of the order of B/B{sub {theta}} or of 1.265{epsilon}{sup 3sol4}B/B{sub {theta}} depending on the plasma parameters when the perturbed neoclassical viscosity driven current is taken into account. Here, B is the magnetic field strength, B{sub {theta}} is the poloidal magnetic field strength, and {epsilon} is the inverse aspect ratio. This effect is illustrated using an existing model for the resistive wall modes by including the neoclassical dissipation in the derivation of the dispersion relation. The derivation is based on fluid equations with the plasma viscosity, calculated using kinetic equation, as the closure. The reduction of the critical toroidal speed is a consequence of the parallel (to the magnetic field B) momentum equation when neoclassical viscosity becomes important. The results are compared with experimental observations in tokamaks.

• OSTI ID: 20643929
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 12 Vol. 11; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DISPERSION RELATIONS
KINETIC EQUATIONS
MAGNETOHYDRODYNAMICS
NEOCLASSICAL TRANSPORT THEORY
PLASMA
TOKAMAK DEVICES
VISCOSITY