Speaker
Mr
Adrianus Sips
(EU)
Description
ITER requires robust operation of various plasma scenarios within the hardware constraints of the device. Operation in H-mode at 15MA and q95=3 is planned to achieve Q=10 in deuterium-tritium mixtures. The Integrated Operation Scenario Topical Group of the ITPA has coordinated experiments in C-Mod, ASDEX Upgrade, DIII-D and JET to obtain optimum data assessing H-mode scenarios at q95~3. Previous results for the plasma formation at low loop voltage and the ramp-up phase were reported.
Recent joint studies on the flat top and ramp down phase show that entering H-mode is generally observed at Ptot/PL-H~1. Regular ELMing H-modes achieving H98~1 require
Ptot/PL-H=1.3-2 at JET, for Ip up to 4.5MA, in DIII-D regular ELMing H-modes are only achieved at higher plasma beta (beta_N=2.0), while in C-Mod Ptot/PL-H~1 is only achieved in stationary H-modes at high input power and higher radiation fraction using seeding. JET data show no significant difference in plasma performance or temperature and density profile shapes when using ion cyclotron heating compared to neutral beam heating, despite the rotation profile changing dramatically when the co-neutral beam is reduced to zero. For H-modes at high plasma current, some experiments only reach ne/nGW~0.65-0.7 using gas fuelling. At DIII-D the stability of long pulse operation at q95=3, shows susceptibility to n=1 tearing modes. The current ramp down requires H-mode combined with a reduction in plasma elongation to control the plasma inductance excursion without additional flux consumption, for ohmic or L-mode discharges a stronger reduction in elongation would be required.
The experimental data presented provide important input for benchmarking integrated code simulations using sophisticated models for transport and heating or current drive systems; moreover they give additional confidence and insight into the possible operation domain of the baseline plasma scenario in ITER.
Country or International Organization of Primary Author
European Union
Collaboration (if applicable, e.g., International Tokamak Physics Activities)
Integrated Operation Scenario Topical Group of the ITPA
Primary author
Mr
Adrianus Sips
(EU)
Co-authors
Ms
Amanda Hubbard
(Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, USA)
Mr
Charles Kessel
(Plasma Physics Laboratory, Princeton University, Princeton, USA)
Mr
Emmanuel Joffrin
(Association Euratom-CEA, Cadarache 13108 Saint Paul Lez Durance, France)
Mr
Gary Jackson
(General Atomics, San Diego, USA)
Mr
Hendrik Hoehnle
(Institut für Plasmaforschung, University Stuttgart, D-70569 Stuttgart, Germany)
Ms
Isabel Nunes
(Euratom/IST Fusion Association, Centro de Fusao Nuclear, Lisboa, Portugal)
Mr
Joerg Hobirk
(Max-Planck-Institut für Plasmaphysik, EURATOM-Association, D-85748, Garching, Germany)
Mr
Joerg Stober
(Max-Planck-Institut für Plasmaphysik, EURATOM-Association, D-85748, Garching, Germany)
Dr
Josef Schweinzer
(IPP Garching)
Mr
Luce Tim
(General Atomics, San Diego, USA)
Mr
Peter Lomas
(EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon OX14 3DB, UK)
Mr
Steve Wolfe
(Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, USA)
