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Vertical displacement and position control in tokamaks

Abstract

Free-boundary nearly rigid displacements are considered in a plasma confined by a magnetic field consisting of one part generated by the plasma current density, and one part being due to steady currents in fixed external conductors. An induced surface current effect and a related force on the plasma arise when the externally applied field is inhomogeneous in the direction of displacement. This additional force has not been taken into account in conventional MHD theory. In the particular case of tokamaks, the induced surface current effect has two impacts on vertical nearly rigid displacements. First, there arises an additional restoring force and a positive contribution to the change in potential energy when the externally applied field is inhomogeneous in the vertical direction. A special design of poloidal field coils can thus provide new means for vertical position control in tokamaks, also in the case of strongly elongated cross-sections. Second, an earlier simplified model, in which the plasma is represented by a line current, has to be modified since the plasma is a highly conducting body of finite size. 4 refs.
Authors:
Publication Date:
Jun 01, 1994
Product Type:
Technical Report
Report Number:
KTH-ALF-R-94-2; TRITA-ALF-94-2.
Reference Number:
SCA: 700300; PA: AIX-26:013536; EDB-95:033093; SN: 95001325483
Resource Relation:
Other Information: PBD: Jun 1994
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TOKAMAK DEVICES; MAGNETIC CONFINEMENT; MAGNETIC FIELDS; MAGNETIC FLUX COORDINATES; MAGNETIC SURFACES; PLASMA DENSITY; PLASMA INSTABILITY; PLASMA RADIAL PROFILES; 700300; PLASMA PHYSICS AND FUSION RESEARCH
OSTI ID:
10112810
Research Organizations:
Royal Inst. of Tech., Stockholm (Sweden). Dept. of Fusion Plasma Physics
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0348-467X; Other: ON: DE95614166; TRN: SE9400200013536
Availability:
OSTI; NTIS; INIS
Submitting Site:
SWDN
Size:
16 p.
Announcement Date:
Jun 30, 2005

Citation Formats

Lehnert, B. Vertical displacement and position control in tokamaks. Sweden: N. p., 1994. Web.
Lehnert, B. Vertical displacement and position control in tokamaks. Sweden.
Lehnert, B. 1994. "Vertical displacement and position control in tokamaks." Sweden.
@misc{etde_10112810,
title = {Vertical displacement and position control in tokamaks}
author = {Lehnert, B}
abstractNote = {Free-boundary nearly rigid displacements are considered in a plasma confined by a magnetic field consisting of one part generated by the plasma current density, and one part being due to steady currents in fixed external conductors. An induced surface current effect and a related force on the plasma arise when the externally applied field is inhomogeneous in the direction of displacement. This additional force has not been taken into account in conventional MHD theory. In the particular case of tokamaks, the induced surface current effect has two impacts on vertical nearly rigid displacements. First, there arises an additional restoring force and a positive contribution to the change in potential energy when the externally applied field is inhomogeneous in the vertical direction. A special design of poloidal field coils can thus provide new means for vertical position control in tokamaks, also in the case of strongly elongated cross-sections. Second, an earlier simplified model, in which the plasma is represented by a line current, has to be modified since the plasma is a highly conducting body of finite size. 4 refs.}
place = {Sweden}
year = {1994}
month = {Jun}
}