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Title: Design of an ion cyclotron resonance heating system for the Compact Ignition Tokamak

Abstract

The Compact Ignition Tokamak (CIT) requires 10-20 MW of ion cyclotron resonance heating (ICRH) power to raise the plasma temperature to ignition. The initial ICRH system will provide 10 MW of power to the plasma, utilizing a total of six rf power units feeding six current straps in three ports. The systems may be expanded to 20 MW with additional rf power units, antennas, and ports. Plasma heating will be achieved through coupling to the fundamental ion cyclotron resonance of a /sup 3/He minority species (also the second harmonic of tritium). The proposed antenna is a resonant double loop (RDL) structure with vacuum, shorted stubs at each end for tuning and impedance matching. The antennas are of modular, compact construction for installation and removal through the midplane port. Remote maintainability and the reactorlike operating environment have a major impact on the design of the launcher for this machine. 6 refs., 7 figs., 5 tabs.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Oak Ridge National Lab., TN (USA)
OSTI Identifier:
7078756
Report Number(s):
CONF-871007-118
ON: DE89001942
DOE Contract Number:
AC05-84OR21400
Resource Type:
Conference
Resource Relation:
Conference: 12. symposium on fusion engineering, Monterey, CA, USA, 12 Oct 1987; Other Information: Paper copy only, copy does not permit microfiche production
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COMPACT IGNITION TOKAMAK; ICR HEATING; DESIGN; ANTENNAS; PERFORMANCE; PLASMA DISRUPTION; RF SYSTEMS; CLOSED PLASMA DEVICES; ELECTRICAL EQUIPMENT; EQUIPMENT; HEATING; HIGH-FREQUENCY HEATING; PLASMA HEATING; THERMONUCLEAR DEVICES; THERMONUCLEAR REACTORS; TOKAMAK DEVICES; TOKAMAK TYPE REACTORS; 700209* - Fusion Power Plant Technology- Component Development & Materials Testing; 700101 - Fusion Energy- Plasma Research- Confinement, Heating, & Production

Citation Formats

Yugo, J.J., Goranson, P.L., Swain, D.W., Baity, F.W., and Vesey, R.. Design of an ion cyclotron resonance heating system for the Compact Ignition Tokamak. United States: N. p., 1987. Web.
Yugo, J.J., Goranson, P.L., Swain, D.W., Baity, F.W., & Vesey, R.. Design of an ion cyclotron resonance heating system for the Compact Ignition Tokamak. United States.
Yugo, J.J., Goranson, P.L., Swain, D.W., Baity, F.W., and Vesey, R.. 1987. "Design of an ion cyclotron resonance heating system for the Compact Ignition Tokamak". United States. doi:. https://www.osti.gov/servlets/purl/7078756.
@article{osti_7078756,
title = {Design of an ion cyclotron resonance heating system for the Compact Ignition Tokamak},
author = {Yugo, J.J. and Goranson, P.L. and Swain, D.W. and Baity, F.W. and Vesey, R.},
abstractNote = {The Compact Ignition Tokamak (CIT) requires 10-20 MW of ion cyclotron resonance heating (ICRH) power to raise the plasma temperature to ignition. The initial ICRH system will provide 10 MW of power to the plasma, utilizing a total of six rf power units feeding six current straps in three ports. The systems may be expanded to 20 MW with additional rf power units, antennas, and ports. Plasma heating will be achieved through coupling to the fundamental ion cyclotron resonance of a /sup 3/He minority species (also the second harmonic of tritium). The proposed antenna is a resonant double loop (RDL) structure with vacuum, shorted stubs at each end for tuning and impedance matching. The antennas are of modular, compact construction for installation and removal through the midplane port. Remote maintainability and the reactorlike operating environment have a major impact on the design of the launcher for this machine. 6 refs., 7 figs., 5 tabs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1987,
month = 1
}

Conference:
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  • Electron Cyclotron Radio Frequency heating of the Compact Ignition Tokamak to ignition utilizing a constant source frequency is proposed. The importance of varying the anomalous conductivity ratio is examined for high density discharges with parabolic density profiles. It is concluded that low to moderate values of the anomalous conductivity ratio are desirable for ignition at reasonable RF and alpha powers, with confinement times of the order of 0.6 sec. (AIP)
  • The Compact Ignition Tokamak (CIT) operating scenario calls for ramping the toroidal magnetic field from B{sub T} = 8.0 to 10.0 Tesla in a few seconds, followed by a burn cycle and a ramp-down cycle. Simultaneously, the plasma must be heated from an initial low beta equilibrium ({bar {beta}} {approx equal} 0.44% at 7.0 to 8.0 Tesla) to a final burn equilibrium ({bar {beta}} = 2.5--5.5%) having 10.0 Tesla on the magnetic axis. This paper proposes ECRF heating of CIT to ignition utilizing a constant source frequency but with a time dependent, variable angle of injection. 10 refs., 3 figs.
  • The Compact Ignition Tokamak (CIT) operating scenario calls for ramping the toroidal magnetic field from B/sub T/ = 7.0 (8.0) to 10.0 Tesla in a few seconds, followed by a burn cycle and a ramp-down cycle. Simultaneously, the plasma must be heated from an initial low beta equilibrium (/bar /beta// approx. = 0.44% at 7.0 to 8.0 Tesla) to a final burn equilibrium (/bar /beta// = 2.8%) having 10.0 Tesla on the magnetic axis. Since the toroidal plasma current will be ramped at the same time and since the available time for flat-top magnetic field must be reserved for themore » burn cycle, it is imperative that densification and heating be carried out as the magnetic field is ramped. Here we examine an approach which is applicable to ECR heating. The frequency remains constant, while the angle of injection is varied by simply rotating a reflecting mirror placed in the path of the incident microwave beam. The rotating mirror permits one to launch waves with sufficiently high N/sub /parallel// so that the Doppler broadened resonance of particles on the magnetic axis with f = 280 GHz and B/sub T/ = 7.0--8.0 Tesla can provide adequate absorption. As the resonance layer moves toward the magnetic axis the beam is swept toward perpendicular to reduce the Doppler width and avoid heating the plasma edge. At B/sub T/ = 10.0 Tesla the beam will be at normal incidence with strong absorption immediately on the high field side of the resonance (relativistic regime). We envisage using the ordinary mode (O-mode, /rvec E//sub RF/ /parallel/ /rvec B/) of polarization which is accessible from the outside (low-field side) of the torus provided the density is such that ..omega../sub pe/ less than or equal to ..omega.. approx. ..omega../sub ce/ (max). 8 refs., 3 figs.« less
  • The theory of scattering by drift-wave density fluctuations is applied to electron-cyclotron heating (ECH) in the Compact Ignition Tokamak (CIT). It is found for CIT that the scattering angles are small and have a Gaussian distribution. An analytic result is given for the average number of scattering events suffered by a ray during propagation through the turbulence layer; this average number is 1.3 for the turbulence level expected in CIT. Localizability of ECH power in CIT is also studied for two choices of steering mirror. Better access to outer flux surfaces and better localization is achieved if the power ismore » steered within a poloidal plane. 7 refs., 3 figs.« less
  • A new form of the dispersion relation of electron cyclotron waves in hot plasmas is used for the study of auxiliary heating in the Compact Ignition Tokamak (CIT). It is shown that the extraordinary mode with a frequency of 190 GHz can be used in CIT plasmas with a central electron density of 1 x 10/sup -15/ cm/sup -3/ and a toroidal magnetic field of 105 kG.