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Title: Determining Of Toroidal Current Density By Measurement Of Horizontal Displacement In IR-T1 Tokamak

Abstract

The measurement of horizontal displacement has been applied to reconstruction of toroidal current density in order to solving Grad-Shafranov equation in tokamak by using inverse problem of the MHD equation method. Then result of this modeling has been compared with experimental data of IR-T1 tokamak.

Authors:
;  [1];  [1];  [2]
  1. Plasma Physics Research Centre, Science and Research Campus, I.A.U, Tehran P.O.Box: 14665-678 (Iran, Islamic Republic of)
  2. (Iran, Islamic Republic of)
Publication Date:
OSTI Identifier:
20797898
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 812; Journal Issue: 1; Conference: PLASMA 2005: International conference on research and applications of plasmas; 3. German-Polish conference on plasma diagnostics for fusion and applications; 5. French-Polish seminar on thermal plasma in space and laboratory, Opole-Turawa (Poland), 6-9 Sep 2005; Other Information: DOI: 10.1063/1.2168823; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CURRENT DENSITY; GRAD-SHAFRANOV EQUATION; MAGNETOHYDRODYNAMICS; PLASMA; PLASMA CONFINEMENT; PLASMA SIMULATION; TOKAMAK DEVICES

Citation Formats

Eshghabadi, M., Rohani, S., Takook, M. V., and Department of Physics, Razi University, Kermanshah. Determining Of Toroidal Current Density By Measurement Of Horizontal Displacement In IR-T1 Tokamak. United States: N. p., 2006. Web. doi:10.1063/1.2168823.
Eshghabadi, M., Rohani, S., Takook, M. V., & Department of Physics, Razi University, Kermanshah. Determining Of Toroidal Current Density By Measurement Of Horizontal Displacement In IR-T1 Tokamak. United States. doi:10.1063/1.2168823.
Eshghabadi, M., Rohani, S., Takook, M. V., and Department of Physics, Razi University, Kermanshah. Sun . "Determining Of Toroidal Current Density By Measurement Of Horizontal Displacement In IR-T1 Tokamak". United States. doi:10.1063/1.2168823.
@article{osti_20797898,
title = {Determining Of Toroidal Current Density By Measurement Of Horizontal Displacement In IR-T1 Tokamak},
author = {Eshghabadi, M. and Rohani, S. and Takook, M. V. and Department of Physics, Razi University, Kermanshah},
abstractNote = {The measurement of horizontal displacement has been applied to reconstruction of toroidal current density in order to solving Grad-Shafranov equation in tokamak by using inverse problem of the MHD equation method. Then result of this modeling has been compared with experimental data of IR-T1 tokamak.},
doi = {10.1063/1.2168823},
journal = {AIP Conference Proceedings},
number = 1,
volume = 812,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • The measurement of current-carrying plasma column displacement is very important for plasma position control. Two methods for this purpose are introduced. In this paper, calculation and construction of these coils is explained. Multiple moment method has been used and derived for construction of sensing coils Also Fourier Transform has been used and derived for continuous coils. The comparison of their advantages are investigated. For IR-T1 Tokamak, Two Cosine coils and two Saddle Sine coils were designed and constructed, which have been placed diametrically around minor radius of torus. Then an electronic circuit was designed for adding and integrating the Cosinemore » and Saddle Sine coils output with proper gain. The contribution of each coils in final output is calculated. For compensation of unwanted pickups voltage from the time varying fields each signal with adjustable gain is added to main signal, until removing the additional field effects. The final output holds good proportionality to H.D.« less
  • Since displacement is very important for plasma position control, in IR-T1 tokamak a combination of two cosine coils and two saddle sine coils is used for horizontal displacement measurement. According to the multiple moment theory, the output of these coils linearly depends to radial displacement of plasma column. A new circuit for adding these signals to feedback system designed and unwanted effects of other fields in final output compensated. After compensation and calibration of the system, the output of horizontal displacement circuits applied to feedback control system. By considers the required auxiliary vertical field, a proportional amplifier and driver circuitmore » are constructed to drive power transistors these power transistors switch the feedback bank capacitors. In the experiment, a good linear proportionality between displacement and output observed by applying an appropriate feedback field, the linger confinement time in IR-T1 tokamak obtained, applying this system to discharge increased the plasma duration and realizes repetitive discharges.« less
  • The modified Rogowski sine-coil (MRSC) has been designed and implemented for the plasma column horizontal displacement measurements on small IR-T1 tokamak. MRSC operation has been examined on test assembly and tokamak. Obtained results show high sensitivity to the plasma column horizontal displacement and negligible sensitivity to the vertical displacement; linearity in wide, {+-}0.1 m, range of the displacements; and excellent, 1.5%, agreement with the results of numerical solution of Biot-Savart and magnetic flux equations.
  • A method for the measurement of the plasma position in the IR-T1 tokamak in toroidal coordinates is developed. A sine-coil, which is a Rogowski coil with a variable wiring density is designed and fabricated for this purpose. An analytic solution of the Biot-Savart law, which is used to calculate magnetic fields created by toroidal plasma current, is presented. Results of calculations are compared with the experimental data obtained in no-plasma shots with a toroidal current-carrying coil positioned inside the vessel to simulate the plasma movements. The results are shown a good linear behavior of plasma position measurements. The error ismore » less than 2.5% and it is compared with other methods of measurements of the plasma position. This method will be used in the feedback position control system and tests of feedback controller parameters are ongoing.« less
  • Studies of plasma interaction with titanium coated ferritic steel is performed on IR-T1 tokamak. Titanium coating is one of the candidates for the plasma facing materials in a tokomak. Titaniumization is carried out by a sputtering method. Some of the samples were baked (3 hours at 460 deg. C) before sputtering. Atomic Force Microscopy (AFM) analyses before and after discharge in r/a = l .04 carried out. The samples (with distinctive titanium layers) were placed at different depths inside the vacuum vessel of the IR-T1 tokamak in the SOL region. A comparison of the titanium coated steel with bare ferriticmore » steel exposed to plasma tokamak and glow discharges is made in this research. Depth of impurity penetration and retention, and the surface roughness are measured by using surface analysis methods. Rutherford backscattering method is used to measure the content of nitrogen, oxygen and titanium, before and after discharges. The result is shown a change in roughness with respect to position of samples.« less