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Title: Loop-voltage tomography in tokamaks using transient synchrotron radiation

Abstract

The loop voltage in tokamaks is particularly difficult to measure anywhere but at the plasma periphery. A brief, deliberate, perturbation of hot plasma electrons, however, produces a transient radiation response that is sensitive to this voltage. We investigate how such a radiation response can be used to diagnose the loop voltage. 24 refs., 6 figs.

Authors:
;  [1];  [2]
  1. (Princeton Univ., NJ (USA). Plasma Physics Lab.
  2. (USA). Dept. of Physics)
Publication Date:
Research Org.:
Princeton Univ., NJ (USA). Plasma Physics Lab.
Sponsoring Org.:
DOE/ER
OSTI Identifier:
5793362
Report Number(s):
PPPL-2637
ON: DE89014343; TRN: 89-019589
DOE Contract Number:
AC02-76CH03073; FG02-84ER53187
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TOKAMAK DEVICES; PLASMA DIAGNOSTICS; ENTROPY; FOKKER-PLANCK EQUATION; GREEN FUNCTION; MAGNETIC SURFACES; RESPONSE FUNCTIONS; SYNCHROTRON RADIATION; TOMOGRAPHY; BREMSSTRAHLUNG; CLOSED PLASMA DEVICES; DIAGNOSTIC TECHNIQUES; DIFFERENTIAL EQUATIONS; ELECTROMAGNETIC RADIATION; EQUATIONS; FUNCTIONS; MAGNETIC FIELD CONFIGURATIONS; PARTIAL DIFFERENTIAL EQUATIONS; PHYSICAL PROPERTIES; RADIATIONS; THERMODYNAMIC PROPERTIES; THERMONUCLEAR DEVICES; 700102* - Fusion Energy- Plasma Research- Diagnostics

Citation Formats

Fisch, N.J., Kritz, A.H., and Hunter Coll., New York, NY. Loop-voltage tomography in tokamaks using transient synchrotron radiation. United States: N. p., 1989. Web. doi:10.2172/5793362.
Fisch, N.J., Kritz, A.H., & Hunter Coll., New York, NY. Loop-voltage tomography in tokamaks using transient synchrotron radiation. United States. doi:10.2172/5793362.
Fisch, N.J., Kritz, A.H., and Hunter Coll., New York, NY. Sat . "Loop-voltage tomography in tokamaks using transient synchrotron radiation". United States. doi:10.2172/5793362. https://www.osti.gov/servlets/purl/5793362.
@article{osti_5793362,
title = {Loop-voltage tomography in tokamaks using transient synchrotron radiation},
author = {Fisch, N.J. and Kritz, A.H. and Hunter Coll., New York, NY},
abstractNote = {The loop voltage in tokamaks is particularly difficult to measure anywhere but at the plasma periphery. A brief, deliberate, perturbation of hot plasma electrons, however, produces a transient radiation response that is sensitive to this voltage. We investigate how such a radiation response can be used to diagnose the loop voltage. 24 refs., 6 figs.},
doi = {10.2172/5793362},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 1989},
month = {Sat Jul 01 00:00:00 EDT 1989}
}

Technical Report:

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  • Calculations of temperature profile of D-fuelled tokamaks using the standard point models for synchrotron radiation and a new transport model are compared. It is shown that transport of radiation has a significant effect on the temperature profile, and that the sensitivity of the profile shape to the net transport loss is comparable to that for thermal conduction.
  • Calculation of energy transport by synchrotron radiation has long been considered as a difficult computational problem, largely due to the non-local nature of the transport which is aggravated by the presence of reflecting walls. We present here a simple physical model which mimics the main features of the transport. A computer code based upon this model is described and test calculations comparing its results to predictions of a full transport calculation are presented. Satisfactory agreement is found, both for the total energy loss and the radial profile of the power density.
  • An elementary qualitative discussion is given of the transport of synchrotron radiation in a magnetized plasma. A summary is given of the actual computational results. These results are compared with the qualitative description of the preceding section. The conclusions to be drawn with respect to both the physics of advanced fuel reactors and better computational methods are outlined.
  • We show by means of an example in a six-dimensional parameter space that induced transient radiation can inform on the dc electric field and other tokamak parameters.
  • High spatial resolution tomography benefits from a high brightness source (photons/(mr{sup 2} x source area)). A synchrotron radiation source provides extremely high continuous brightness with spectral characteristics suited to a wide variety of imaging needs. Therefore, during the initial testing of the new synchrotron radiation computed tomography (SRCT) system at Stanford Synchrotron Radiation Laboratory, it was suggested that we image a ruled target designed for NIF experiments. This is a detailed report of that imaging effort.