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Title: Design, construction, and first operational results of a 5 megawatt feedback controlled amplifier system for disruption control on the Columbia University HBT-EP tokamak

Abstract

This paper presents the electrical design and first operational results of a 5 Megawatt feedback controlled amplifier system designed to drive a 300 uH saddle coil set on the ``HBT-EP`` tokamak. It will be used to develop various plasma feedback techniques to control and inhibit the onset of plasma disruptions that are observed in high ``B`` plasmas. To provide a well characterized system, a high fidelity, high power closed loop amplifier system has been refurbished from the Los Alamos ``ZT-P`` equilibrium feedback system. In it`s configuration developed for the Columbia HBT-EP tokamak, any desired waveform may be generated within a I 100 ampere and 16 kV peak to peak dynamic range. An energy storage capacitor bank presently limits the effective full power pulse width to 10 mS. The full power bandwidth driving the saddle coil set is {approximately}12 kHz, with bandwidth at reduced powers exceeding 30 kHz. The system is designed similar to a grounded cathode, push-pull, transformer coupled, tube type amplifier system. `Me push pull amplifier consists of 6 each Machlett ML8618 magnetically beamed triodes, 3 on each end of the (center tapped) coupling transformer. The transformer has .I volt-seconds of core and a 1:1 turns ratio. The transformermore » is specially designed for high power, low leakage inductance, and high bandwidth. Each array of ML8618`s is (grid) driven with a fiber optic controlled hotdeck with a 3CXI0,000A7 (triode) output. To linearize the ML8618 grid drive, a minor feedback loop in the hotdeck is utilized. Overall system response is controlled by active feedback of the saddle coil current, derived from a coaxial current viewing resistor. The detailed electrical design of the power amplifier, transformer, and feedback system will be provided in addition to recent HBT-EP operational results.« less

Authors:
; ; ;  [1]; ;  [2]
  1. Los Alamos National Lab., NM (United States)
  2. Columbia Univ., New York, NY (United States)
Publication Date:
Research Org.:
Los Alamos National Lab., NM (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
204123
Report Number(s):
LA-UR-95-4280; CONF-950750-49
ON: DE96005603; TRN: 96:008613
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: 10. Institute of Electrical and Electronics Engineers (IEEE) pulsed power conference, Albuquerque, NM (United States), 10-13 Jul 1995; Other Information: PBD: [1995]
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; COLUMBIA HIGH-BETA TOKAMAK; POWER AMPLIFIERS; PERFORMANCE TESTING; DESIGN; FABRICATION; FEEDBACK; ELECTRIC CONTROLLERS

Citation Formats

Reass, W A, Alvestad, H A, Bartsch, R R, Wurden, G A, Ivers, T H, and Nadle, D L. Design, construction, and first operational results of a 5 megawatt feedback controlled amplifier system for disruption control on the Columbia University HBT-EP tokamak. United States: N. p., 1995. Web.
Reass, W A, Alvestad, H A, Bartsch, R R, Wurden, G A, Ivers, T H, & Nadle, D L. Design, construction, and first operational results of a 5 megawatt feedback controlled amplifier system for disruption control on the Columbia University HBT-EP tokamak. United States.
Reass, W A, Alvestad, H A, Bartsch, R R, Wurden, G A, Ivers, T H, and Nadle, D L. Sun . "Design, construction, and first operational results of a 5 megawatt feedback controlled amplifier system for disruption control on the Columbia University HBT-EP tokamak". United States. https://www.osti.gov/servlets/purl/204123.
@article{osti_204123,
title = {Design, construction, and first operational results of a 5 megawatt feedback controlled amplifier system for disruption control on the Columbia University HBT-EP tokamak},
author = {Reass, W A and Alvestad, H A and Bartsch, R R and Wurden, G A and Ivers, T H and Nadle, D L},
abstractNote = {This paper presents the electrical design and first operational results of a 5 Megawatt feedback controlled amplifier system designed to drive a 300 uH saddle coil set on the ``HBT-EP`` tokamak. It will be used to develop various plasma feedback techniques to control and inhibit the onset of plasma disruptions that are observed in high ``B`` plasmas. To provide a well characterized system, a high fidelity, high power closed loop amplifier system has been refurbished from the Los Alamos ``ZT-P`` equilibrium feedback system. In it`s configuration developed for the Columbia HBT-EP tokamak, any desired waveform may be generated within a I 100 ampere and 16 kV peak to peak dynamic range. An energy storage capacitor bank presently limits the effective full power pulse width to 10 mS. The full power bandwidth driving the saddle coil set is {approximately}12 kHz, with bandwidth at reduced powers exceeding 30 kHz. The system is designed similar to a grounded cathode, push-pull, transformer coupled, tube type amplifier system. `Me push pull amplifier consists of 6 each Machlett ML8618 magnetically beamed triodes, 3 on each end of the (center tapped) coupling transformer. The transformer has .I volt-seconds of core and a 1:1 turns ratio. The transformer is specially designed for high power, low leakage inductance, and high bandwidth. Each array of ML8618`s is (grid) driven with a fiber optic controlled hotdeck with a 3CXI0,000A7 (triode) output. To linearize the ML8618 grid drive, a minor feedback loop in the hotdeck is utilized. Overall system response is controlled by active feedback of the saddle coil current, derived from a coaxial current viewing resistor. The detailed electrical design of the power amplifier, transformer, and feedback system will be provided in addition to recent HBT-EP operational results.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1995},
month = {12}
}

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