Convective momentum transport, shock viscosity, and the L--H transition in tokamaks

Journal Article · Sun Aug 01 04:00:00 EDT 1993 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860684· OSTI ID:6324158

Shaing, K C ^[1]; Hsu, C T ^[2]

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1. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States)
2. Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

Convective momentum transport associated with [bold V][center dot][del][bold V] in the momentum equation is calculated for arbitrary values of the poloidal [bold E][times][bold B] Mach number [ital M][sub [ital p]]. Here, [bold V] is the plasma flow velocity. The physics origin of the convective momentum transport is associated with the coupling of the poloidal variation of the viscosity-driven flux to that of the flow velocity in the magnetic surface. When the radial gradient scale length of the plasma velocity is of the order of the ion poloidal gyroradius, [rho][sub [ital pi]], the convective momentum transport becomes comparable to the ion viscosity. At [ital M][sub [ital p]][congruent]1, the ion viscosity associated with shock---the shock viscosity---approximately balances the convective momentum transport to maintain the lowest-order ambipolarity. The implications of the effects of shock and convective momentum transport for the previous L--H transition bifurcation theory [K. C. Shaing and E. C. Crume, Jr., Phys. Rev. Lett. [bold 63], 2369 (1989)] are discussed, and an extended bifurcation theory including these effects is presented. It is shown that the experimentally relevant plasma viscosity, [ital effective] [ital plasma] [ital viscosity], is very similar to that obtained without including compressibility effects, even if shock exists.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6324158
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 5:8; ISSN 0899-8221; ISSN PFBPEI
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700330* -- Plasma Kinetics
Transport
& Impurities-- (1992-)
CLOSED PLASMA DEVICES
CONVECTION
ENERGY TRANSFER
HEAT TRANSFER
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC SURFACES
MASS TRANSFER
MOMENTUM TRANSFER
PLASMA
ROTATING PLASMA
SHOCK WAVES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRANSPORT
VISCOSITY