On the definition of Pfirsch--Schlueter and bootstrap currents in toroidal systems

Journal Article · Fri May 01 04:00:00 EDT 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860085· OSTI ID:7234458

Coronado, M ^[1]; Wobig, H ^[2]

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1. Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510 Mexico, D.F. (Mexico)
2. Max-Planck-Institut fuer Plasmaphysik, 8046 Garching (bei Muenchen) (Germany)

In the plasma physics literature there appear two different definitions of Pfirsch--Schlueter current. One of them is predominantly used in equilibrium calculations and satisfies the condition {ital I}{sub {ital T}}=0. The other definition appears commonly in transport calculations and requires that the surface average of the dot product of the Pfirsch--Schlueter current density with the magnetic field vanish, i.e., {l angle}{bold J}{sub PS}{center dot}{bold B}{r angle}=0. The difference between the definitions is a surface function. Within the framework of the moment equation approach, the total parallel current is completely determined through a surface average of Ohm's law; thus different definitions of Pfirsch--Schlueter current imply different expressions for the bootstrap current. Understanding the different implications of these two definitions is of particular importance when designing toroidal devices with minimized Pfirsch--Schlueter current or studying tokamaks with optimized bootstrap current. In this paper the definitions of Pfirsch--Schlueter and bootstrap current, as well as the expressions for the corresponding Pfirsch--Schlueter diffusion flux, are analyzed and discussed for the case of axisymmetric and nonaxisymmetric plasmas. Although in cases like a current-free stellarator or a large-aspect-ratio tokamak both definitions are equivalent, they are in general different, and in order to avoid misunderstandings it is therefore important to use only one. The most appropriate definition is {ital I}{sub {ital T}}=0. In this paper the equations for determining the bootstrap current within the framework of the fluid equations are also analyzed.

• OSTI ID: 7234458
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 4:5; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700330* -- Plasma Kinetics
Transport
& Impurities-- (1992-)
ANNULAR SPACE
CLOSED CONFIGURATIONS
CLOSED PLASMA DEVICES
CONFIGURATION
CONFINEMENT
CURRENT DENSITY
FLUID MECHANICS
HYDRODYNAMICS
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC SURFACES
MAGNETOHYDRODYNAMICS
MECHANICS
NEOCLASSICAL TRANSPORT THEORY
OHM LAW
PFIRSCH-SCHLUETER REGIME
PLASMA CONFINEMENT
SPACE
STELLARATORS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TOROIDAL CONFIGURATION
TRANSPORT THEORY