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Regimes and Edge Behaviour
on the COMPASS-D Tokamak with High Power ECRH and LHCD
A. W. Morris, S. J. Fielding, M. Valovic,
P. G. Carolan, J. W. Connor, A. R. Field, B. Lloyd,
C. Warrick, H. R. Wilson, the COMPASS-D Team and the
RF Team
EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxfordshire, OX14 3DB, UK
Abstract. COMPASS-D, due to its small size (R=0.56m, a=0.18m) and long pulse
length (relative to field diffusion times), provides valuable data when
establishing the underlying physics and scalings for H-mode thresholds,
confinement, and ELM behaviour for devices of the scale of ITER. It is found
that the H-mode threshold has a very different parametric behaviour than that
observed on larger devices, and new edge data provides a possible
explanation. An adaptable 60GHz ECRH system has allowed high power ECRH (1.8MW
installed power) to be used over a wide range of plasma parameters from low
collisionality high to high density H-modes. This system injects
neither particles nor momentum, and is thus representative of the situation on
ITER. A 1.3GHz 400kW LHCD system has provided additional flexibility for
long pulse operation and optimisation of high discharges
(e.g. to avoid disruptions).
IAEA 2001
