Alternative methods of vertical plasma control in the Alcator C-Mod Tokamak

This thesis investigates alternate methods of controlling the vertical position of the plasma in the ALCATOR C-Mod Tokamak. The purpose of this work is to examine alternative methods of controlling the plasma position that can be adopted to improve performance over the current system, which uses a proportional-derivative (PD) control system actuated through a pair of outboard equilibrium field coils (EFC). The first part of this investigation examines the possibility of using inboard ohmic heating coils (OH2) as the controlling coils. A coupling transformer was designed to connect a large amperage/low bandwidth power supply to a small amperage/high bandwidth power supply, removing the need for an expensive large and fast power supply. Both PD control laws and full state feedback laws were also compared for performance. A rigid displacement model of the plasma motion was developed that took into account a model of induced currents in the vacuum vessel and coils. The results of the analysis concluded that there were moderate speed advantages to using state feedback on The OH2 coils, but these were outweighed by the robust operation of EFC PD control. No design achieved a decisive margin of improvement over the current control system.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Nuclear Science and Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1998

Author dc:creator

• Miller, G. H. (George Hugh)

Advisor dc:contributor.advisor

• Ian H. Hutchinson.

• Nuclear Engineering

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/50489

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/50489