skip to main content

SciTech ConnectSciTech Connect

Title: Characteristics of a novel lower hybrid wave antenna for the TST-2 spherical tokamak

A new type of traveling wave antenna which excites the lower hybrid wave directly was developed. This antenna is similar to the inductively-coupled combline antenna in that only the first element of the antenna array is excited externally, and subsequent elements are excited passively by mutual coupling between adjacent elements. The main difference is that whereas the inductively-coupled combline antenna makes use of mutual inductance, the presently proposed antenna makes use of mutual capacitance. The radiating elements are located at the voltage maximum, and the electric field induced in the plasma is in the toroidal direction rather than the poloidal direction, matching the polarization of the lower hybrid wave. Optimization studies were carried out to obtain a band-pass characteristic centered around 200 MHz, and a unidirectional wavenumber spectrum with the parallel index of refraction corresponding to approximately 5. Plasma current ramp-up to 2 kA has been achieved on the TST-2 spherical tokamak with 12 kW of RF power at 200 MHz during the initial experimental period using this antenna. Further optimization studies are being performed.
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1] ;  [2]
  1. The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa 277-8561 (Japan)
  2. General Atomics, San Diego, CA 92186 (United States)
Publication Date:
OSTI Identifier:
22263891
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1580; Journal Issue: 1; Conference: 20. topical conference on radiofrequency power in plasmas, Sorrento (Italy), 25-28 Jun 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANTENNAS; APPROXIMATIONS; COUPLING; ELECTRIC CURRENTS; ELECTRIC FIELDS; ELECTRIC POTENTIAL; LOWER HYBRID HEATING; PLASMA; POLARIZATION; REFRACTIVE INDEX; SPECTRA; TOKAMAK DEVICES; TRAVELLING WAVES