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Combined analysis of steady state and transient transport by the maximum entropy method

Abstract

A new maximum entropy approach has been applied to analyse three types of transient transport experiments. For sawtooth propagation experiments in the ASDEX Upgrade and ECRH power modulation and power-switching experiments in the Wendelstein 7-AS Stellarator, either the time evolution of the temperature perturbation or the phase and amplitude of the modulated temperature perturbation are used as non-linear constraints to the {chi}{sub e} profile to be fitted. Simultaneously, the constraints given by the equilibrium temperature profile for steady-state power balance are fitted. In the maximum entropy formulation, the flattest {chi}{sub e} profile consistent with the constraints is found. It was found that {chi}{sub e} determined from sawtooth propagation was greater than the power balance value by a factor of five in the ASDEX Upgrade. From power modulation experiments, employing the measurements of four modulation frequencies simultaneously, the power deposition profile as well as the {chi}{sub e} profile could be determined. A comparison of the predictions of a time-independent {chi}{sub e} model and a power-dependent {chi}{sub e} model is made. The power-switching experiments show that the {chi}{sub e} profile must change within a millisecond to a new value consistent with the power balance value at the new input power. Neither power  More>>
Authors:
Giannone, L.; Stroth, U; Koellermeyer, J [1] 
  1. Association Euratom-Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); and others
Publication Date:
Apr 01, 1996
Product Type:
Journal Article
Report Number:
CONF-9506282-
Reference Number:
SCA: 700330; PA: AIX-27:058576; EDB-96:124415; SN: 96001635783
Resource Relation:
Journal Name: Plasma Physics and Controlled Fusion; Journal Volume: 38; Journal Issue: 4; Conference: 22. European conference on controlled fusion and plasmas physics, Bournemouth (United Kingdom), 3-7 Jun 1995; Other Information: DN: Extended version of a poster paper.; PBD: Apr 1996
Subject:
70 PLASMA PHYSICS AND FUSION; ENTROPY; PLASMA; STEADY-STATE CONDITIONS; TRANSIENTS; HEAT TRANSFER; BREAKEVEN; ELECTRONS; THERMAL CONDUCTIVITY; CHARGED-PARTICLE TRANSPORT; SAWTOOTH OSCILLATIONS; WAVE PROPAGATION
OSTI ID:
267383
Country of Origin:
United Kingdom
Language:
English
Other Identifying Numbers:
Journal ID: PPCFET; ISSN 0741-3335; TRN: GB9600918058576
Submitting Site:
GBN
Size:
pp. 477-488
Announcement Date:

Citation Formats

Giannone, L., Stroth, U, and Koellermeyer, J. Combined analysis of steady state and transient transport by the maximum entropy method. United Kingdom: N. p., 1996. Web. doi:10.1088/0741-3335/38/4/003.
Giannone, L., Stroth, U, & Koellermeyer, J. Combined analysis of steady state and transient transport by the maximum entropy method. United Kingdom. doi:10.1088/0741-3335/38/4/003.
Giannone, L., Stroth, U, and Koellermeyer, J. 1996. "Combined analysis of steady state and transient transport by the maximum entropy method." United Kingdom. doi:10.1088/0741-3335/38/4/003. https://www.osti.gov/servlets/purl/10.1088/0741-3335/38/4/003.
@misc{etde_267383,
title = {Combined analysis of steady state and transient transport by the maximum entropy method}
author = {Giannone, L., Stroth, U, and Koellermeyer, J}
abstractNote = {A new maximum entropy approach has been applied to analyse three types of transient transport experiments. For sawtooth propagation experiments in the ASDEX Upgrade and ECRH power modulation and power-switching experiments in the Wendelstein 7-AS Stellarator, either the time evolution of the temperature perturbation or the phase and amplitude of the modulated temperature perturbation are used as non-linear constraints to the {chi}{sub e} profile to be fitted. Simultaneously, the constraints given by the equilibrium temperature profile for steady-state power balance are fitted. In the maximum entropy formulation, the flattest {chi}{sub e} profile consistent with the constraints is found. It was found that {chi}{sub e} determined from sawtooth propagation was greater than the power balance value by a factor of five in the ASDEX Upgrade. From power modulation experiments, employing the measurements of four modulation frequencies simultaneously, the power deposition profile as well as the {chi}{sub e} profile could be determined. A comparison of the predictions of a time-independent {chi}{sub e} model and a power-dependent {chi}{sub e} model is made. The power-switching experiments show that the {chi}{sub e} profile must change within a millisecond to a new value consistent with the power balance value at the new input power. Neither power deposition broadening due to suprathermal electrons nor temperature or gradient dependences of {chi}{sub e} can explain this observation. (author).}
doi = {10.1088/0741-3335/38/4/003}
journal = {Plasma Physics and Controlled Fusion}
issue = {4}
volume = {38}
journal type = {AC}
place = {United Kingdom}
year = {1996}
month = {Apr}
}