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Abstract

In order to simultaneously control the current and pressure profiles in high performance tokamak plasmas with internal transport barriers (ITB), a multi-variable model-based technique has been proposed. New algorithms using a truncated singular value decomposition (TSVD) of a linearized model operator and retaining the distributed nature of the system have been implemented in the JET control system. Their simplest versions have been applied to the control of the current density profile in reversed shear plasmas using three heating and current drive actuators (neutral beam injection, ion cyclotron resonant frequency heating and lower hybrid current drive). Successful control of the safety factor profile has been achieved in the quasi-steady-state, on a timescale of the order of the current redistribution time. How the TSVD algorithm will be used in the forthcoming campaigns for the simultaneous control of the current profile and of the ITB temperature gradient is discussed in some detail, but this has not yet been attempted in the present pioneering experiments.

Additional information

Authors: MOREAU D ET AL, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR) and EFDA-JET Close Support Unit, Culham Science Centre, Abingdon (GB);CRISANTI F, Associazione Euratom-ENEA sulla Fusione, C.R. Frascati, Frascati (IT);PERICOLI-RIDOLFINI V, Associazione Euratom-ENEA sulla Fusione, C.R. Frascati, Frascati (IT);RIVA M, Associazione Euratom-ENEA sulla Fusione, C.R. Frascati, Frascati (IT);DE VRIES P, Euratom-FOM Association, TEC Cluster, Nieuwegein (NL);FELTON R, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);ZASTROW K D, EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);MURARI A, Associazione Euratom-ENEA, Consorzio RFX, Padova (IT);TALA T, Association EURATOM-TEKES, VTT (FI)
Bibliographic Reference: An article published in: Nuclear Fusion 43 (2003) pp.870�882
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at:http://stacks.iop.org/NF/43/870
Record Number: 200316841 / Last updated on: 2003-10-08
Category: PUBLICATION
Original language: en
Available languages: en