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Title: Initial Design of the 60 Megawatt Rotating Magnetic Field (RMF) Oscillator System for the University of Washington ''TCS'' Field Reversed Configuration Experiment

Abstract

This paper presents the initial electrical and mechanical design of two phase-locked 30 Megawatt RMS, 150 kHz oscillator systems used for current drive and plasma sustainment of the ''Translation, Confinement, and Sustainment'' (TCS) field reversed configuration (FRC) plasma. By the application of orthogonally-placed saddle coils on the surface of the glass vacuum vessel, the phase-controlled rotating magnetic field perturbation will induce an electric field in the plasma which should counter the intrinsic ohmic decay of the plasma, and maintain the FRC. Each system utilizes a bank of 6 parallel magnetically beamed ML8618 triodes. These devices are rated at 250 Amperes cathode current and a 45 kV plate voltage. An advantage of the magnetically beamed triode is their extreme efficiency, requiring only 2.5 kW of filament and a few amps and a few kV of grid drive. Each 3.5 uH saddle coil is configured with an adjustable tank circuit (for tuning). Assuming no losses and a nominal 18 kV plate voltage, the tubes can circulate about 30 kV and 9 kA (pk to pk) in the saddle coil antenna, a circulating power of over 33 megawatts RMS. On each cycle the tubes can kick in up to 1500 Amperes, providing amore » robust phase control. DC high-voltage from the tubes is isolated from the saddle coil antennas and tank circuits by a 1:1 coaxial air-core balun transformer. To control the ML8618's phase and amplitude, fast 150 Ampere ''totem-pole'' grid drivers, an ''on'' hot-deck and an ''off'' hot-deck are utilized. The hot-decks use up to 6 each 3CPX1500A7 slotted radial beam triodes. By adjusting the conduction angle, amplitude may be regulated, with inter-pulse timing, phase angle can be controlled. A central feedback timing chassis monitors each systems' saddle coil antenna and appropriately derives each systems timing signals. Fiber-optic cables are used to isolate between the control room timing chassis and the remote power oscillator system. Complete system design detail will be presented in addition to anticipated (computer generated) performance characteristics. Initial design and construction began in FY97, and will continue through FY98, with delivery to the experiment in FY99, for commencement of physics experiments on sustaining the FRC.« less

Authors:
; ;
Publication Date:
Research Org.:
Los Alamos National Lab., NM (US)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
762879
Report Number(s):
LA-UR-98-135
TRN: US0100138
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: 17th IEEE Symposium on Fusion Engineering, San Diego, CA (US), 10/06/1997--10/10/1997; Other Information: PBD: 6 Oct 1997
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CONFIGURATION; CONTROL ROOMS; DESIGN; ELECTRIC FIELDS; MAGNETIC FIELDS; OSCILLATORS; TANK CIRCUITS; WASHINGTON

Citation Formats

Reass, W A, Miera, D A, and Wurden, G A. Initial Design of the 60 Megawatt Rotating Magnetic Field (RMF) Oscillator System for the University of Washington ''TCS'' Field Reversed Configuration Experiment. United States: N. p., 1997. Web.
Reass, W A, Miera, D A, & Wurden, G A. Initial Design of the 60 Megawatt Rotating Magnetic Field (RMF) Oscillator System for the University of Washington ''TCS'' Field Reversed Configuration Experiment. United States.
Reass, W A, Miera, D A, and Wurden, G A. Mon . "Initial Design of the 60 Megawatt Rotating Magnetic Field (RMF) Oscillator System for the University of Washington ''TCS'' Field Reversed Configuration Experiment". United States. https://www.osti.gov/servlets/purl/762879.
@article{osti_762879,
title = {Initial Design of the 60 Megawatt Rotating Magnetic Field (RMF) Oscillator System for the University of Washington ''TCS'' Field Reversed Configuration Experiment},
author = {Reass, W A and Miera, D A and Wurden, G A},
abstractNote = {This paper presents the initial electrical and mechanical design of two phase-locked 30 Megawatt RMS, 150 kHz oscillator systems used for current drive and plasma sustainment of the ''Translation, Confinement, and Sustainment'' (TCS) field reversed configuration (FRC) plasma. By the application of orthogonally-placed saddle coils on the surface of the glass vacuum vessel, the phase-controlled rotating magnetic field perturbation will induce an electric field in the plasma which should counter the intrinsic ohmic decay of the plasma, and maintain the FRC. Each system utilizes a bank of 6 parallel magnetically beamed ML8618 triodes. These devices are rated at 250 Amperes cathode current and a 45 kV plate voltage. An advantage of the magnetically beamed triode is their extreme efficiency, requiring only 2.5 kW of filament and a few amps and a few kV of grid drive. Each 3.5 uH saddle coil is configured with an adjustable tank circuit (for tuning). Assuming no losses and a nominal 18 kV plate voltage, the tubes can circulate about 30 kV and 9 kA (pk to pk) in the saddle coil antenna, a circulating power of over 33 megawatts RMS. On each cycle the tubes can kick in up to 1500 Amperes, providing a robust phase control. DC high-voltage from the tubes is isolated from the saddle coil antennas and tank circuits by a 1:1 coaxial air-core balun transformer. To control the ML8618's phase and amplitude, fast 150 Ampere ''totem-pole'' grid drivers, an ''on'' hot-deck and an ''off'' hot-deck are utilized. The hot-decks use up to 6 each 3CPX1500A7 slotted radial beam triodes. By adjusting the conduction angle, amplitude may be regulated, with inter-pulse timing, phase angle can be controlled. A central feedback timing chassis monitors each systems' saddle coil antenna and appropriately derives each systems timing signals. Fiber-optic cables are used to isolate between the control room timing chassis and the remote power oscillator system. Complete system design detail will be presented in addition to anticipated (computer generated) performance characteristics. Initial design and construction began in FY97, and will continue through FY98, with delivery to the experiment in FY99, for commencement of physics experiments on sustaining the FRC.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1997},
month = {10}
}

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