Open and emerging control problems in tokamak plasma control

Abstract

Tbe tokamak concept for magnetic confinement of fusion plasmas is now quite mature scientifically. This maturity is evidenced by tbe ongoing worldwide effort to design and construct an internationally supported multi-billion dollar experimental tokamak called ITER, wbose purpose is to demonstrate the scientific and technical feasibility of fusion energy as 8 power source. To achieve its scientific objectives, tbe ITER device will need to implement solutions to several challenging control problems. Some solutions to tbese control problems are already mature, e.g. control of the plasma boundary sbape and stabilization of the vertical stability, but many otber solutions are currently in development or do not yet have viable solution approaches. In almost all cases, control solutions developed on existing tokamaks are made more challenging on ITER by safety issues arising from its nuclear mission and control actuation margins tbat are reduced due to cost considerations. However, many of these problems must ha\'e robust solutions in place before ITER comes online in approximately 2016. In this paper, we summarize a set of the most urgently needed control solutions and describe the progress made toward solving a few of these problems.

A Strict Control Lyapunov Function for a Diffusion Equation With Time-Varying Distributed Coefficients

“…A detailed account of tokamak physics can be found in [36]. An overview of challenges of tokamak plasma control is given in [24] and [35].…”

ATCA Advanced Control and Data Acquisition Systems for Fusion Experiments

“…The important 0018-9499/$26.00 © 2010 IEEE and increasing role that real-time control is playing in the operation of fusion experiments is mainly due to the need to optimize the plasma performance which requires adequate feedback control processes, with an increasing number of plasma parameters [16]. Active feedback control systems are used to control global plasma parameters such as the plasma position, shape, heating, current drive, stabilization, and start-up and safe termination of discharges [17]. Furthermore, considerable effort is underway to enhance the plasma confinement and achieve the so-called Advanced Tokamak regimes [18].…”

Lyapunov-based distributed control of the safety-factor profile in a tokamak plasma

“…In particular, an adequate control of the safety factor profile or q-profile, which is determined by the relationship between the toroidal and the poloidal components of the magnetic field, is very important for the plasma discharge MHD stability and possible enhanced energy confinement. An overview of emerging and existing challenges of tokamak plasma control is given in [1,2]. For a discussion on advanced tokamak scenarios, refer for instance to [3,4] and [5].…”