Dependence of the energy lifetime on the type of anomalous losses in stellarators

Journal Article · Tue Jul 15 04:00:00 EDT 2008 · Plasma Physics Reports

DOI:https://doi.org/10.1134/S1063780X08070015· OSTI ID:21400007

Kovrizhnykh, L M ^[1]

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1. Russian Academy of Sciences, Prokhorov Institute of General Physics (Russian Federation)

A relatively simple model of transport process in stellarators that was proposed earlier by the author on the basis of neoclassical theory makes it possible to determine the density and temperature profiles of the plasma components, the ambipolar electric field profile, and the particle and energy lifetimes from the given device parameters and given particle and energy sources with allowance for anomalous losses. The results of numerical simulations carried out with this model for the L-2M, ATF, CHS, and LHD stellarators over broad ranges of plasma densities and absorbed powers showed that the plasma energy lifetimes in these devices coincide to within factors on the order of two with those found from empirical scalings. A specific model of anomalous losses was chosen for calculations. Results are presented from simulations with a more general form of the anomalous thermal conductivity. Namely, the thermal conductivity is chosen to be K{sub j}{sup (a)} {approx} N{sup {alpha}T}{sub j}{sup {beta}B}{sub 0}{sup -{gamma}}, where N(r) is the plasma density and T{sub j}(r) is the temperature of the jth plasma component (j = e, i). The parameters {alpha}, {beta}, and {gamma} are set equal to {alpha} = 1, {beta} = 2, and {gamma} = 1; {alpha} = 0.5, {beta} = 2.5, and {gamma} = 1; {alpha} = 1.5, {beta} = 2, and {gamma} = 2; {alpha} = 1, {beta} = 2.5, and {gamma} = 2; and {alpha} = 1.5, {beta} = 2.5, and {gamma} = 2. The simulations have been done for the L-2M and LHD stellarators. It is found that, in all the five models, the calculated energy lifetimes {tau}{sub c} are essentially independent of the functional form of the anomalous thermal conductivity and coincide to within a factor on the order of two with those following from the LHD scaling.

• OSTI ID: 21400007
• Journal Information: Plasma Physics Reports, Journal Name: Plasma Physics Reports Journal Issue: 7 Vol. 34; ISSN PPHREM; ISSN 1063-780X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CHARGED-PARTICLE TRANSPORT THEORY
CLOSED PLASMA DEVICES
COMPUTERIZED SIMULATION
ELECTRIC FIELDS
LHD DEVICE
LIFETIME
NEOCLASSICAL TRANSPORT THEORY
PHYSICAL PROPERTIES
PLASMA
PLASMA DENSITY
SCALING
SIMULATION
STELLARATORS
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
THERMONUCLEAR DEVICES
TRANSPORT THEORY