Integrated plasma controls for steady state scenarios

Joffrin, E.; Barana, O.; Mazon, D.; Moreau, Ph.; Turco, F.; Artaud, Jean-François; Basiuk, V.; Bourdelle, C.; Brémond, S.; Bucalossi, J.; Clairet, F.; Colas, L.; Corre, Y.; Dümont, R.; Giruzzi, G.; Goniche, M.; Imbeaux, F.; Kazarian, F.; Laborde, Laurent; Monier‐Garbet, P.; Maget, P.; Pégouriè, B.; Peysson, Y.; Rimini, F.; Saint‐Laurent, F.; Tsitrone, E.

doi:10.1088/0029-5515/47/12/004

Cited by 13 publications

(6 citation statements)

References 20 publications

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“…In particular for such long pulse experiments, the surface temperature of key components (such as the radio frequency antennas and the limiter) is detected by means of infrared cameras. As a consequence, the ICRH power is sometimes reduced during the experiment by the control algorithm in order to maintain the machine integrity (as demonstrated in earlier Tore Supra experiments [19]). This does not interfere directly with the q-profile control algorithm, which acts on the LH power.…”

Section: Control Strategymentioning

confidence: 99%

Real-time control of the safety factor profile diagnosed by magneto-hydrodynamic activity on the Tore Supra tokamak

Imbeaux¹,

Lennholm²,

Pastor³

et al. 2011

Nucl. Fusion

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Real-time control is essential for many aspects of tokamak operation. A key parameter to control is the current profile, since both confinement properties and magneto-hydrodynamic (MHD) activity depend on it in quite a sensitive way. The long pulse capability of the Tore Supra tokamak has allowed a unique type of experiment, where successive stationary states of the safety factor profile, defined by their MHD activity, are established and controlled in real time. Multiple target stationary states could be requested and reached during the main heating phase of a single plasma discharge. Experiments have been carried out featuring (i) control of the presence/absence of sawteeth with varying plasma parameters, (ii) obtaining and sustaining a ‘hot core’ plasma regime without MHD activity and (iii) recovery from a voluntarily triggered deleterious MHD regime. During these experiments, the influence of fast ions on MHD stability could be observed and characterized, as well as indications of an enhanced ‘hot core’ confinement in electron heat transport during quiescent MHD states.

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Section: Control Strategymentioning

confidence: 99%

Real-time control of the safety factor profile diagnosed by magneto-hydrodynamic activity on the Tore Supra tokamak

Imbeaux¹,

Lennholm²,

Pastor³

et al. 2011

Nucl. Fusion

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“…Operation scenarios with reduced intrinsic tendency to disrupt should be found, and control techniques must be developed to both maintain those optimal equilibrium characteristics and to prevent the growth of disruptive magnetohydrodynamic (MHD) instabilities. Examples of equilibrium control techniques include control of the strongly shaped plasma boundary [37,38], the global β N [39][40][41], the internal profiles [42][43][44][45], or error fields [46,47]. With regard to instability control, the vertical position instability [48][49][50][51][52] is controlled [50][51][52] as a matter of routine in all shaped tokamaks.…”

Section: Introductionmentioning

confidence: 99%

Detection of disruptions in the high-βspherical torus NSTX

et al. 2013

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This paper describes the prediction of disruptions based on diagnostic data in the high-β spherical torus NSTX (Ono et al 2000 Nucl. Fusion 40 557). The disruptive threshold values on many signals are examined. In some cases, raw diagnostic data can be used as a signal for disruption prediction. In others, the deviations of the plasma data from simple models provides the information used to determine the proximity to disruption. However, no single signal or calculation and associated threshold value can form the basis for disruption prediction in NSTX; thresholds that produce an acceptable false-positive rate have too large a missed or late-warning rate, while combinations that produce an acceptable rate of missed or late warnings have an unacceptable false-positive rate. To solve this problem, a novel means of combining multiple threshold tests has been developed. After being properly tuned, this algorithm can produce a false-positive rate of 2.8%, with a late + missed warning rate of 3.7% and thus a total failure rate of 6.5%, when applied to a database of ∼2000 disruptions during the IP flat top collected from three run campaigns. Furthermore, many of these false positives are triggered by near-disruptive magnetohydrodynamic (MHD) events that might indeed be disruptive in larger plasmas with more stored energy. However, the algorithm is less efficient at detecting the MHD event that prompts the disruption process.

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“…Operations scenarios with reduced intrinsic disruptivity should be found, and control techniques must be developed to both maintain those optimal equilibrium characteristics and to prevent the growth of disruptive MHD. Examples of equilibrium control techniques include control of the strongly shaped plasma boundary [37,38], the global β N [39][40][41], the internal profiles [42][43][44][45], or error fields [46,47]. The vertical position instability [48][49][50][51][52] is controlled [50][51][52] as a matter of routine in all shaped tokamaks.…”

Section: : Introductionmentioning

confidence: 99%