Optimization of Outer Poloidal Field (PF) Coil Configurations for Inductive PF Coilonly Plasma Startup on Spherical Tori
Abstract
The elimination of inboard ohmic heating solenoid is required for the spherical torus (ST) to function as an attractive fusion power plant. An inboard ohmic solenoid, along with the shielding needed for its insulation, increases the size and, hence, the cost of the plant. Here, we investigate using static as well as dynamic codes in ST geometries a solenoidfree startup concept utilizing a set of outboard poloidal field coils. By using the static code, an optimization of coil positions as well as coil currents was performed to demonstrate that it is indeed possible to create a high quality multipole field null region while retaining significant flux (voltseconds) needed for the subsequent current rampup. With the dynamic code that includes the effect of vacuum vessel eddy currents, we then showed that it is possible to maintain a large size field null region for several milliseconds in which sufficient ionization avalanche can develop in the applied toroidal electric field. Under the magnetic geometry typical of a next generation spherical torus experiment, it is shown that the wellknown plasma breakdown conditions for conventional ohmic solenoid startup of E(sub)TB(sub)T/B(sub)P {approx} (0.11) kV/m with V(sub)loop {approx} 6 V can be readily met while retaining significantmore »
 Authors:
 Publication Date:
 Research Org.:
 Princeton Plasma Physics Lab., Princeton, NJ (US)
 Sponsoring Org.:
 USDOE Office of Science (SC) (US)
 OSTI Identifier:
 827828
 Report Number(s):
 PPPL3939
TRN: US0403708
 DOE Contract Number:
 AC0276CH03073
 Resource Type:
 Technical Report
 Resource Relation:
 Other Information: PBD: 9 Apr 2004
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BREAKDOWN; EDDY CURRENTS; ELECTRIC CURRENTS; ELECTRIC FIELDS; GEOMETRY; HEATING; IONIZATION; OPTIMIZATION; PLASMA; POWER PLANTS; SHIELDING; SOLENOIDS; STARTUP; OHMIC HEATING; SPHERICAL TORUS; SOLENOIDFREE STARTUP; POLOIDAL FIELD COIL; INDUCTIVE
Citation Formats
Wonho Choe, Jayhyun Kim, and Masayuki Ono. Optimization of Outer Poloidal Field (PF) Coil Configurations for Inductive PF Coilonly Plasma Startup on Spherical Tori. United States: N. p., 2004.
Web. doi:10.2172/827828.
Wonho Choe, Jayhyun Kim, & Masayuki Ono. Optimization of Outer Poloidal Field (PF) Coil Configurations for Inductive PF Coilonly Plasma Startup on Spherical Tori. United States. doi:10.2172/827828.
Wonho Choe, Jayhyun Kim, and Masayuki Ono. Fri .
"Optimization of Outer Poloidal Field (PF) Coil Configurations for Inductive PF Coilonly Plasma Startup on Spherical Tori". United States.
doi:10.2172/827828. https://www.osti.gov/servlets/purl/827828.
@article{osti_827828,
title = {Optimization of Outer Poloidal Field (PF) Coil Configurations for Inductive PF Coilonly Plasma Startup on Spherical Tori},
author = {Wonho Choe and Jayhyun Kim and Masayuki Ono},
abstractNote = {The elimination of inboard ohmic heating solenoid is required for the spherical torus (ST) to function as an attractive fusion power plant. An inboard ohmic solenoid, along with the shielding needed for its insulation, increases the size and, hence, the cost of the plant. Here, we investigate using static as well as dynamic codes in ST geometries a solenoidfree startup concept utilizing a set of outboard poloidal field coils. By using the static code, an optimization of coil positions as well as coil currents was performed to demonstrate that it is indeed possible to create a high quality multipole field null region while retaining significant flux (voltseconds) needed for the subsequent current rampup. With the dynamic code that includes the effect of vacuum vessel eddy currents, we then showed that it is possible to maintain a large size field null region for several milliseconds in which sufficient ionization avalanche can develop in the applied toroidal electric field. Under the magnetic geometry typical of a next generation spherical torus experiment, it is shown that the wellknown plasma breakdown conditions for conventional ohmic solenoid startup of E(sub)TB(sub)T/B(sub)P {approx} (0.11) kV/m with V(sub)loop {approx} 6 V can be readily met while retaining significant voltseconds {approx} 4 VS sufficient to generate multiMA plasma current in STs.},
doi = {10.2172/827828},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Apr 09 00:00:00 EDT 2004},
month = {Fri Apr 09 00:00:00 EDT 2004}
}

Two versions of the Fusion Engineering Design Center (FEDC) freeboundary equilibrium code designed to computer the poloidal field (PF) coil current distribution of elongated, magnetically limited tokamak plasmas are demonstrated and applied to the systems analysis of the impact of plasma elongation on the design point of the International Thermonuclear Experimental Reactor (ITER). These notes were presented at the ITER Specialists' Meeting on the PF Coil System and Operational Scenario, held at the Max Planck Institute for Plasma Physics in Garching, Federal Republic of Germany, May 2427, 1988. 8 refs., 6 figs., 4 tabs.

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