Synergetic heating of D-NBI ions in the vicinity of the mode conversion layer in H-D plasmas in JET with the ITER like wall.

EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK.
¹ Laboratory for Plasma Physics, LPP-ERM/KMS, TEC Partner, 1000 Brussels, Belgium.
² Culham Centre for Fusion Energy (CCFE), Culham Science Centre, Abingdon, OX14 3DB, UK.
³ Department of Physics and Astronomy, Uppsala University, Sweden.
⁴ KTH Royal Institute of Technology, 114 28 Stockholm, Sweden.
⁵ Barcelona Supercomputing Center (BSC), 08034 Barcelona, Spain.
⁶ ICREA, Pg. Lluis Companys 23, 08010 Barcelona, Spain.
⁷ Dipartimento di Fisica, Universita di Milano-Bicocca, 20126, Milan, Italy.
⁸ Istituto di Fisica del Plasma, CNR, 20125 Milan, Italy.
⁹ Max-Planck-Institut fur Plasmaphysik, 85748 Garching, Germany.
¹⁰ ENEA Centro Ricerche, Frascati, Italy.
¹¹ Department of Applied Physics, Ghent University, 9000 Gent, Belgium.
¹² Institute of Plasma Physics and Laser Microfusion, 01-497 Warsaw, Poland.
¹³ CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
¹⁴ Max-Planck-Institut fur Plasmaphysik, 17491 Greifswald, Germany
¹⁵ Institute for Nuclear Research, Kyiv, 03680, Ukraine.
¹⁶ EPFL, Swiss Plasma Center (SPC), 1015 Lausanne, Switzerland.
¹⁷ Instituto de Plasmas e Fusao Nuclear, IST, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
¹⁸ ITER Organization, Route de Vignon-sur-Verdon, 13067 St Paul-lez-Durance Cedex, France.
¹⁹ Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, MA 02139, USA.

^* Corresponding author: j.ongena@fz-juelich.de

Published online: 23 October 2017

Abstract

This paper discusses the extension of the ‘three-ion’ species ICRF technique for heating mixture plasmas using fast injected NBI ions as resonant ‘third’ species. In this scenario the ICRF power is absorbed by the fast beam ions in the vicinity of the mode conversion layer where the left-hand polarized RF electric field E₊ is strongly enhanced. The ions in the beam velocity distribution that have a Doppler-shifted resonance close to the mode conversion layer efficiently absorb RF power and undergo acceleration. We show first experimental observations of ICRF heating of D-NBI ions in H-D plasmas in JET with the ITER-like wall. In agreement with theoretical predictions and numerical modelling, acceleration of the D-NBI ions in this D-(D_NBI)-H scenario is confirmed by several fast-ion measurements. An extension of the heating scheme discussed here is acceleration of T-NBI and D-NBI ions in D-T plasmas, offering the potential to further boost the Q-value in future D-T campaigns in JET.