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Title: A novel feedback algorithm for simulating controlled dynamics and confinement in the advanced reversed-field pinch

Abstract

In the advanced reversed-field pinch (RFP), the current density profile is externally controlled to diminish tearing instabilities. Thus the scaling of energy confinement time with plasma current and density is improved substantially as compared to the conventional RFP. This may be numerically simulated by introducing an ad hoc electric field, adjusted to generate a tearing mode stable parallel current density profile. In the present work a current profile control algorithm, based on feedback of the fluctuating electric field in Ohm's law, is introduced into the resistive magnetohydrodynamic code DEBSP [D. D. Schnack and D. C. Baxter, J. Comput. Phys. 55, 485 (1984); D. D. Schnack, D. C. Barnes, Z. Mikic, D. S. Marneal, E. J. Caramana, and R. A. Nebel, Comput. Phys. Commun. 43, 17 (1986)]. The resulting radial magnetic field is decreased considerably, causing an increase in energy confinement time and poloidal {beta}. It is found that the parallel current density profile spontaneously becomes hollow, and that a formation, being related to persisting resistive g modes, appears close to the reversal surface.

Authors:
;  [1]
  1. Alfven Laboratory, Royal Institute of Technology, 10044 Stockholm (Sweden)
Publication Date:
OSTI Identifier:
20764315
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 12; Journal Issue: 6; Other Information: DOI: 10.1063/1.1924556; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CONFINEMENT TIME; CURRENT DENSITY; FEEDBACK; PLASMA CONFINEMENT; PLASMA SIMULATION; REVERSE-FIELD PINCH; TEARING INSTABILITY

Citation Formats

Dahlin, J.-E., and Scheffel, J. A novel feedback algorithm for simulating controlled dynamics and confinement in the advanced reversed-field pinch. United States: N. p., 2005. Web. doi:10.1063/1.1924556.
Dahlin, J.-E., & Scheffel, J. A novel feedback algorithm for simulating controlled dynamics and confinement in the advanced reversed-field pinch. United States. doi:10.1063/1.1924556.
Dahlin, J.-E., and Scheffel, J. Wed . "A novel feedback algorithm for simulating controlled dynamics and confinement in the advanced reversed-field pinch". United States. doi:10.1063/1.1924556.
@article{osti_20764315,
title = {A novel feedback algorithm for simulating controlled dynamics and confinement in the advanced reversed-field pinch},
author = {Dahlin, J.-E. and Scheffel, J.},
abstractNote = {In the advanced reversed-field pinch (RFP), the current density profile is externally controlled to diminish tearing instabilities. Thus the scaling of energy confinement time with plasma current and density is improved substantially as compared to the conventional RFP. This may be numerically simulated by introducing an ad hoc electric field, adjusted to generate a tearing mode stable parallel current density profile. In the present work a current profile control algorithm, based on feedback of the fluctuating electric field in Ohm's law, is introduced into the resistive magnetohydrodynamic code DEBSP [D. D. Schnack and D. C. Baxter, J. Comput. Phys. 55, 485 (1984); D. D. Schnack, D. C. Barnes, Z. Mikic, D. S. Marneal, E. J. Caramana, and R. A. Nebel, Comput. Phys. Commun. 43, 17 (1986)]. The resulting radial magnetic field is decreased considerably, causing an increase in energy confinement time and poloidal {beta}. It is found that the parallel current density profile spontaneously becomes hollow, and that a formation, being related to persisting resistive g modes, appears close to the reversal surface.},
doi = {10.1063/1.1924556},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 6,
volume = 12,
place = {United States},
year = {2005},
month = {6}
}