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Abstract

An important experimental programme is in progress on JET to investigate plasma control schemes which, with a limited number of actuators, could eventually enable ITER to sustain steady state burning plasmas in an "advanced tokamak" operation scenario. A multi-variable model-based technique was recently developed for the simultaneous control of several plasma parameter profiles in discharges with internal transport barriers (ITB), using lower hybrid current drive (LHCD) together with neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH). The proposed distributed-parameter control scheme relies on the experimental identification of an integral linear response model operator and retains the intrinsic couplings between the plasma parameter profiles. A first set of experiments was performed to control the current density profile in the low-density/low-power LH-driven phase of the JET advanced scenarios, using only one actuator (LHCD) and a simplified (lumped-parameter) version of the control scheme. Several requested steady state magnetic equilibria were thus obtained and sustained for about 7s, up to full relaxation of the ohmic current throughout the plasma. A second set of experiments was dedicated to the control of the q-profile with 3 actuators (LHCD, NBI and ICRH) during the intense heating phase of advanced scenarios. The safety factor profile was also shown to approach a requested profile within about 5s. The achieved plasma equilibrium was close to steady state. Finally, during the recent high power experimental campaign, experiments have been conducted in a 3T/1.7MA plasma, achieving the simultaneous control of the current density and electron temperature profiles in ITB plasmas. Here, the distributed-parameter version of the algorithm was used for the first time, again with 3 actuators.

Additional information

Authors: MOREAU D, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);LABORDE L, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);LITAUDON X, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);MAZON D, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);ZABEO L, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);JOFFRIN E, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);LENNHOLM M, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);CRISANTI F, Associazione Euratom-ENEA sulla Fusione, Centro.Richerche Energia ENEA-Frascati, Frascati (IT);PERICOLI-RIDOLFINI V, Associazione Euratom-ENEA sulla Fusione, Centro.Richerche Energia ENEA-Frascati, Frascati (IT);RIVA M, Associazione Euratom-ENEA sulla Fusione, Centro.Richerche Energia ENEA-Frascati, Frascati (IT);TUCCILLO A, Associazione Euratom-ENEA sulla Fusione, Centro.Richerche Energia ENEA-Frascati, Frascati (IT);MURARI A, Associazione Euratom-ENEA sulla Fusione, Consorzio RFX, Padova (IT);TALA T, Association EURATOM-TEKES, Helsinki University of Technology (FI);ALBANESE R, Euratom-ENEA Association, CREATE, Napoli (IT) EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);ARIOLA M, Euratom-ENEA Association, CREATE, Napoli (IT) EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);DE TOMMASI G, Euratom-ENEA Association, CREATE, Napoli (IT) EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);PIRONTI A, Euratom-ENEA Association, CREATE, Napoli (IT) EURATOM-UKAEA Fusion Association, Culham Science Centre, Abingdon (GB);FELTON R., FOM Instituut voor Plasmafyisica Rijnhuizen, Euratom-FOM Association, Trilateral Euregio Cluster, Nieuwegein (NL);ZASTROW K D, FOM Instituut voor Plasmafyisica Rijnhuizen, Euratom-FOM Association, Trilateral Euregio Cluster, Nieuwegein (NL);DE BAAR M, Euratom-CIEMAT Association, CIEMAT, Madrid (ES);DE VRIES P, Euratom-CIEMAT Association, CIEMAT, Madrid (ES);DE LA LUNA E,
Bibliographic Reference: An oral paper given at: 20th IAEA Fusion Energy Conference Organised by: International Atomic Energy Agency Held at: Centrtro de Fusao Nuclear, Vilamoura (PT)
Availability: Available from Association EURATOM-CEA, Departement de Recherches sur la Fusion Controlee, CEA Cadarache, F-13108 St Paul-Lez-Durance, France Tel: (+33) 4 42 25 70 01; Fax: (+33) 4 42 25 64 21 E-mail: dirdrfc@drfc.cad.cea.fr
Record Number: 200417774 / Last updated on: 2004-11-10
Category: PUBLICATION
Original language: en
Available languages: en