The history of research into improved confinement
regimes

Wagner, F.

doi:10.1140/epjh/e2016-70064-9

Cited by 23 publications

(26 citation statements)

References 106 publications

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“…Recent work has led to a merger, of sorts, between the two lines of research focusing on density limits and confinement transitions, as schematized in figure (1). In particular, two experimental studies have reported findings that link the decay of the ubiquitous edge shear layer (in L mode) and a concomitant increase in turbulent particle flux to the approach n/n G → 1.…”

Section: Introductionmentioning

confidence: 99%

Bounds on edge shear layer persistence while approaching the density limit

Singh

Diamond

2021

Nucl. Fusion

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This paper details the theory of edge shear layer collapse as the density approaches the Greenwald density limit. It significantly extends earlier work, which was restricted in applicability. The zonal shear flow screening length is calculated for banana, plateau and Pfirsch–Schluter regimes. Poloidal field scaling persists in the plateau regime. Neoclassical screening and drift wave–zonal flow dynamics are combined in a theory, which is then reduced to a predator–prey model. Zonal noise, due to incoherent mode coupling, is retained. The threshold condition for edge shear layer collapse is computed, and linked to a critical value of the dimensionless parameter ρ s / ρ s c L n . Here ρ s is the ion sound radius, ρ s c is the zonal flow screening length and L n is the equilibrium density scale length. The limiting initial edge density for shear layer collapse is derived and shown to scale favorably with the plasma current. The results are discussed in light of the density limit and Ohmic phenomenology.

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Section: Introductionmentioning

confidence: 99%

Bounds on edge shear layer persistence while approaching the density limit

Singh

Diamond

2021

Nucl. Fusion

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“…Upon using in (6) the fact that the L-H transition occurs when Ploss,i > ∼ P L−H,i , the criterion on P L−H for the L-H transition becomes…”

Section: Phenomenological Model For the L-h Power Thresholdmentioning

confidence: 99%

“…Immediately after the H-mode discovery [1], a correlation between sawtooth crash and L-H transition was observed [5]: A heat wave which propagates towards the plasma edge is associated with the sawtooth crash, and because of the correlation between sawtooth crash and the formation of the ETB, the heat wave was thought to be the cause of the ETB formation [5]. At that time, however, it was not clear whether this heat wave was carried by all the plasma species, or only by one and which [6]. It became clear that ion-heat flux was the real responsible for the creation of the ETB, only when preciser measurements of the ion temperature were available and thanks to dedicated experiments with dominant ion heating, e.g.…”

Section: Introductionmentioning

confidence: 99%

Heuristic model for the power threshold of the L-H transition

et al. 2020

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“…The history of improved confinement regimes is narrated in Ref. 9, which also gives the most relevant references.…”

Section: Confinement Of High-temperature Fusion Plasmasmentioning

confidence: 99%

Fusion energy

Wagner

2018

MRS Energy & Sustainability

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Fusion energy is one of the options to contribute to the energy demand of future generations without adding to global warming. In this paper, we present the status of fusion energy research on the basis of magnetic confinement.Fusion energy is one of the options to contribute to the energy demand of future generations without contributing to global warming. In this paper, we present the status of fusion energy research on the basis of magnetic confinement. In France, the first fusion reactor ITER is under construction. Its success will be measured on the expectation to deliver 500 MW thermal power-a factor of 10 above the power to maintain the energy producing process. ITER is based on the tokamak concept. In addition, Wendelstein 7-X, an ambitious stellarator, has recently started operation. Both confinement concepts-the tokamak and the stellarator-will be discussed along with general topics regarding fusion technology, operational safety, fusion waste, possible electricity costs, and roadmaps toward a fusion reactor as a power source. RevIew DISCUSSION POINTS• ITER will demonstrate the feasibility of fusion energy.• The use of fusion energy will be inherently safe and not pollute the environment.• There is an urgent need to develop fusion materials which can withstand the harsh environment of high neutron and power fluxes.• Renewable energies will not be able to meet the demand of all energy consuming sectors in highly developed industrial countries. Therefore, all carbon-free energy sources should be developed including fast fission reactors, CCS-technologies, and fusion.

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The history of research into improved confinement regimes

Cited by 23 publications

References 106 publications

Bounds on edge shear layer persistence while approaching the density limit

Bounds on edge shear layer persistence while approaching the density limit

Heuristic model for the power threshold of the L-H transition

Fusion energy

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