Real-time control of the current density profile in JET
In order to 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 . It uses a truncated singular value decomposition of a linearised model operator and offers the potentiality of retaining the distributed character of the current and heat diffusion (distributed-parameter system) . Here, we describe first experiments using the simplest, lumped-parameter, version of this technique. It will be shown that with only one actuator (LHCD = Lower Hybrid Current Drive), a satisfactory control of the safety factor profile (q-profile) can be achieved within the accessible one-parameter family of profiles, i.e. with a steady state offset between the requested profile and the achieved one which is minimum in the least square sense. In section 4, the first experiments using a multiple-input-multiple-output (MIMO) controller to control the q-profile with three heating and current drive actuators, namely Neutral Beam Injection (NBI), Ion Cyclotron Resonant Heating (ICRH) and LHCD, are reported. Finally in section 5 will be presented a simulation of the simultaneous control of plasma current density and pressure profile by using a state space method to obtain a linear mode of the plasma dynamics.
Bibliographic Reference: An oral paper given at: 45th Annual meeting of the APS Division of Plasma Physics Organised by: American Institute of Physics Held at: Albuquerque, New Mexico
Availability: Available from Association EURATOM-CEA, Département de Recherches sur la Fusion Contrôlée, 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: email@example.com
Record Number: 200517962 / Last updated on: 2005-03-08
Original language: en
Available languages: en