L-H transition in tokamaks and stellarators

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:10158256

Shaing, K C ^[1]; Hsu, C T ^[2]; Christenson, P J ^[3]

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1. Oak Ridge National Lab., TN (United States)
2. Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center
3. Michigan Univ., Ann Arbor, MI (United States). Dept. of Nuclear Engineering

It is shown that the bifurcation dynamics in the H-mode theory based on the ion orbit loss and nonlinear viscosity is not sensitive to the radial pressure and temperature gradients after bifurcation. This allows the poloidal flow velocity to be opposite to that of the poloidal E x B velocity in the H-mode phase if the pressure gradient is steep. Here, E(B) is the electric (magnetic) field. The theory is also extended to stellarator configurations to demonstrate that the tokamak H-mode theory can be tested in a controlled manner in those devices. A set of poloidal and toroidal momentum evolution equations is derived in which the radial current density outside the last closed flux surface is expressed in terms of the radial integral of the poloidal current density into the diverter plates. This facilitates the calculation of the radial electric field profile across the separatrix.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 10158256
• Report Number(s): CONF-9311147--8; ON: DE94013257
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700310
H-MODE PLASMA CONFINEMENT
PLASMA CONFINEMENT
PRESSURE GRADIENTS
STELLARATORS
TEMPERATURE GRADIENTS
TOKAMAK DEVICES