Optimal regimes for ignition and the Ignitor experiment

Coppi, B.; Airoldi, A.; Bombarda, F.; Cenacchi, G.; Detragiache, P.; Sugiyama, L.

doi:10.1088/0029-5515/41/9/314

Cited by 58 publications

(42 citation statements)

References 14 publications

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“…In the proposed high B-field burning plasma experiments, such as IGNITOR [216] and FIRE [217], α E,crit significantly exceeds the nominal α E values of reference scenarios [213]. Thus, EPMs are not expected to be an issue on these devices.…”

Section: Epms and Avalanchesmentioning

confidence: 99%

Chapter 5: Physics of energetic ions

et al. 2007

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This chapter reviews the progress accomplished since the redaction of the first ITER Physics Basis Nucl. Fusion 39 2137 in the field of energetic ion physics and its possible impact on burning plasma regimes. New schemes to create energetic ions simulating the fusion-produced alphas are introduced, accessing experimental conditions of direct relevance for burning plasmas, in terms of the Alfvénic Mach number and of the normalised pressure gradient of the energetic ions, though orbit characteristics and size cannot always match those of ITER. Based on the experimental and theoretical knowledge of the effects of the toroidal magnetic field ripple on direct fast ion losses, ferritic inserts in ITER are expected to provide a significant reduction of ripple alpha losses in reversed shear configurations. The nonlinear fast ion interaction with kink and tearing modes is qualitatively understood, but quantitative predictions are missing, particularly for the stabilisation of sawteeth by fast particles that can trigger neoclassical tearing modes. A large database on the linear stability properties of the modes interacting with energetic ions, such as the Alfvén eigenmode has been constructed. Comparisons between theoretical predictions and experimental measurements of mode structures and drive/damping rates approach a satisfactory degree of consistency, though systematic measurements and theory comparisons of damping and drive of intermediate and high mode numbers, the most relevant for ITER, still need to be performed. The nonlinear behaviour of Alfvén eigenmodes close to marginal stability is well characterized theoretically and experimentally, which gives the opportunity to extract some information on the particle phase space distribution from the measured instability spectral features. Much less data exists for strongly unstable scenarios, characterised by nonlinear dynamical processes leading to energetic ion redistribution and losses, and identified in nonlinear numerical simulations of Alfvén eigenmodes and energetic particle modes. Comparisons with theoretical and numerical analyses are needed to assess the potential implications of these regimes on burning plasma scenarios, including in the presence of a large number of modes simultaneously driven unstable by the fast ions.

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Section: Epms and Avalanchesmentioning

confidence: 99%

Chapter 5: Physics of energetic ions

et al. 2007

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“…Thus, a natural extension of the existing magnetic control systems is to add the control of the magnetic field structure inside the plasma using the OH coil as the actuator, without relying on (but benefiting from) the availability of non inductive current drive sources. The scheme would be particularly useful for the start up and termination phases of future pulsed reactors such as ITER [36] and high field ignition designs such as Ignitor [37], as well as of present day tokamak research facilities. In a tokamak, the transformer primary is the main current profile actuator during the plasma current ramp up phase, responsible for building almost the whole of the plasma current up to its flat-top value.…”

Section: Introductionmentioning

confidence: 99%

Sliding mode control of a tokamak transformer

Romero¹,

Coda

Felici

et al. 2012

2012 IEEE 51st IEEE Conference on Decision and Control (CDC)

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A novel inductive control system for a tokamak transformer is described. The system uses the flux change provided by the transformer primary coil to control either the electric current or the internal inductance of the transformer's secondary plasma circuit load. The internal inductance control is used to regulate the slow flux penetration due to the skin effect, providing first-order control over the shape of the plasma current density profile in the highly conductive plasma. Inferred loop voltages at specific locations inside the plasma are included in a state feedback structure to improve controller performance. Experimental tests have shown that the plasma internal inductance can be controlled inductively for a whole pulse starting just 30ms after the beginning of plasma breakdown. The details of the control system design are presented, including the transformer model, observer algorithms and controller design.

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“…In IGNITOR [1], the FWL is everywhere close to the main plasma. The design is optimized to allow spreading the plasma heat flux onto a relatively large area, reducing the peak values.…”

Section: Introductionmentioning

confidence: 99%