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Title: Helicity content and tokamak applications of helicity

Journal Article · · Phys. Fluids; (United States)
DOI:https://doi.org/10.1063/1.865756· OSTI ID:7242152

Magnetic helicity is approximately conserved by the turbulence associated with resistive instabilities of plasmas. To generalize the application of the concept of helicity, the helicity content of an arbitrary bounded region of space will be defined. The definition has the virtues that both the helicity content and its time derivative have simple expressions in terms of the poloidal and toroidal magnetic fluxes, the average toroidal loop voltage and the electric potential on the bounding surface, and the volume integral of ExB. The application of the helicity concept to tokamak plasmas is illustrated by a discussion of so-called MHD (magnetohydrodynamic) current drive, an example of a stable tokamak q profile with q less than 1 in the center, and a discussion of the possibility of a natural steady-state tokamak due to the bootstrap current coupling of tearing instabilities.

Research Organization:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
OSTI ID:
7242152
Journal Information:
Phys. Fluids; (United States), Vol. 29:12
Country of Publication:
United States
Language:
English