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Title: Alternative RF coupling configurations for H{sup −} ion sources

RF heated sources for negative hydrogen ions both for fusion and accelerators require very high RF powers in order to achieve the required H{sup −} current what poses high demands on the RF generators and the RF circuit. Therefore it is highly desirable to improve the RF efficiency of the sources. This could be achieved by applying different RF coupling concepts than the currently used inductive coupling via a helical antenna, namely Helicon coupling or coupling via a planar ICP antenna enhanced with ferrites. In order to investigate the feasibility of these concepts, two small laboratory experiments have been set up. The PlanICE experiment, where the enhanced inductive coupling is going to be investigated, is currently under assembly. At the CHARLIE experiment systematic measurements concerning Helicon coupling in hydrogen and deuterium are carried out. The investigations show that a prominent feature of Helicon discharges occurs: the so-called low-field peak. This is a local improvement of the coupling efficiency at a magnetic field strength of a few mT which results in an increased electron density and dissociation degree. The full Helicon mode has not been achieved yet due to the limited available RF power and magnetic field strength but it mightmore » be sufficient for the application of the coupling concept to ion sources to operate the discharge in the low-field-peak region.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)
  2. (Germany)
  3. AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany)
Publication Date:
OSTI Identifier:
22391426
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1655; Journal Issue: 1; Conference: NIBS 2014: 4. International Symposium on Negative Ions, Beams and Sources, Garching (Germany), 6-10 Oct 2014; Other Information: (c) 2015 U.S. Government; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 07 ISOTOPES AND RADIATION SOURCES; ANTENNAS; COUPLING; DEUTERIUM; DISSOCIATION; EFFICIENCY; ELECTRIC CURRENTS; ELECTRON DENSITY; HYDROGEN; HYDROGEN IONS 1 MINUS; ION SOURCES; MAGNETIC FIELDS; RF SYSTEMS