Sawtooth pacing with on-axis ICRH modulation in JET-ILW
EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK
1 CCFE, Culham Science Centre, Abingdon, United Kingdom
2 LPP-ERM/KMS, Association EUROFUSION-Belgian State, TEC partner, Brussels, Belgium
3 Instituto de Plasmas e Fusão Nuclear, EUROFUSION-IST, University of Lisbon, Portugal
4 CRPP-EPFL, Association EUROFUSION - Confédération Suisse, Lausanne, Switzerland
5 Consorzio RFX, Association EUROFUSION – CNR/ENEA, Padova, Italy
Published online: 23 October 2017
A novel technique for sawteeth control in tokamak plasmas using ion-cyclotron resonance heating (ICRH) has been developed in the JET-ILW tokamak . Unlike previous ICRH methods, which explored the destabilization of the internal kink mode when the radiofrequency (RF) wave absorption was placed near the q=1 surface, the technique presented here consists of stabilizing the sawteeth as fast as possible by applying the ICRH power centrally and inducing a sawtooth crash by switching it off at the appropriate instant. Since it employs on-axis ICRH, this technique is aligned with other ICRH applications that require central plasma heating such as high-Z impurity control and fusion power enhancement. The validation of this method in JET-ILW L-mode discharges is presented.
© The authors, published by EDP Sciences, 2017
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.