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Thermal diffusivity from heat wave propagation in Wendelstein 7-AS

Abstract

Electron thermal diffusivity studies can be carried out in two ways: static and dynamic. In the static analysis, the transport coefficients are determined from the stationary power balance, in the dynamic analysis from the propagation of a small perturbation of the stationary plasma state which can be caused by either a sawtooth generated heat pulse or modulation of the heating power. Electron thermal diffusivity [chi][sub e] is deduced from the evolution of the perturbed electron temperature T[sub e] at different locations r[sub i] in the plasma. [chi][sub e] values obtained from perturbation analysis are usually greater than those calculated from power balance. It has been pointed out that there is a principal difference between static and perturbative analysis. Whereas the static method yields the transport coefficient [chi][sub e]=q[sub e]/n[sub e][nabla]T[sub e], the perturbative method leads to an increase of the flux q[sub e] as a result of an increase in the temperature gradient [nabla]T[sub e]. The quantity determined is an incremental [chi][sub e] as defined by [chi][sub e][sup inc]=[partial derivative]q[sub e]/n[sub e][partial derivative]([nabla]T[sub e]). By varying the modulation of the heating power at different frequencies and amplitudes one can address the question whether or not this discrepancy is a function  More>>
Authors:
Hartfuss, H J; Erckmann, V; Giannone, L.; Maassberg, H; Tutter, M [1] 
  1. Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)
Publication Date:
Jan 01, 1991
Product Type:
Conference
Report Number:
CONF-9106293-
Reference Number:
AIX-24-043838; EDB-93-081744
Resource Relation:
Journal Name: Europhysics Conference Abstracts; (Switzerland); Journal Volume: 15C:Part II; Conference: 18. European conference on controlled fusion and plasma heating, Berlin (Germany), 3-7 Jun 1991
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; HEAT TRANSFER; WAVE PROPAGATION; WENDELSTEIN-7 STELLARATOR; THERMAL DIFFUSIVITY; AMPLITUDES; DISTURBANCES; DYNAMICS; ECR HEATING; ELECTRON TEMPERATURE; ENERGY BALANCE; EXPERIMENTAL DATA; FREQUENCY DEPENDENCE; HEAT FLUX; SAWTOOTH OSCILLATIONS; TEMPERATURE GRADIENTS; CLOSED PLASMA DEVICES; DATA; ENERGY TRANSFER; HEATING; HIGH-FREQUENCY HEATING; INFORMATION; MECHANICS; NUMERICAL DATA; OSCILLATIONS; PHYSICAL PROPERTIES; PLASMA HEATING; STELLARATORS; THERMODYNAMIC PROPERTIES; THERMONUCLEAR DEVICES; 700350* - Plasma Production, Heating, Current Drive, & Interactions- (1992-)
OSTI ID:
6457335
Country of Origin:
Switzerland
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0378-2271; CODEN: ECABDW
Submitting Site:
CHN
Size:
Pages: II-213-II-216
Announcement Date:
May 13, 2001

Citation Formats

Hartfuss, H J, Erckmann, V, Giannone, L., Maassberg, H, and Tutter, M. Thermal diffusivity from heat wave propagation in Wendelstein 7-AS. Switzerland: N. p., 1991. Web.
Hartfuss, H J, Erckmann, V, Giannone, L., Maassberg, H, & Tutter, M. Thermal diffusivity from heat wave propagation in Wendelstein 7-AS. Switzerland.
Hartfuss, H J, Erckmann, V, Giannone, L., Maassberg, H, and Tutter, M. 1991. "Thermal diffusivity from heat wave propagation in Wendelstein 7-AS." Switzerland.
@misc{etde_6457335,
title = {Thermal diffusivity from heat wave propagation in Wendelstein 7-AS}
author = {Hartfuss, H J, Erckmann, V, Giannone, L., Maassberg, H, and Tutter, M}
abstractNote = {Electron thermal diffusivity studies can be carried out in two ways: static and dynamic. In the static analysis, the transport coefficients are determined from the stationary power balance, in the dynamic analysis from the propagation of a small perturbation of the stationary plasma state which can be caused by either a sawtooth generated heat pulse or modulation of the heating power. Electron thermal diffusivity [chi][sub e] is deduced from the evolution of the perturbed electron temperature T[sub e] at different locations r[sub i] in the plasma. [chi][sub e] values obtained from perturbation analysis are usually greater than those calculated from power balance. It has been pointed out that there is a principal difference between static and perturbative analysis. Whereas the static method yields the transport coefficient [chi][sub e]=q[sub e]/n[sub e][nabla]T[sub e], the perturbative method leads to an increase of the flux q[sub e] as a result of an increase in the temperature gradient [nabla]T[sub e]. The quantity determined is an incremental [chi][sub e] as defined by [chi][sub e][sup inc]=[partial derivative]q[sub e]/n[sub e][partial derivative]([nabla]T[sub e]). By varying the modulation of the heating power at different frequencies and amplitudes one can address the question whether or not this discrepancy is a function of the varied parameters. (author) 7 refs., 2 figs.}
journal = []
volume = {15C:Part II}
place = {Switzerland}
year = {1991}
month = {Jan}
}