Multifaceted physics of edge plasma in magnetic fusion devices

Krasheninnikov, S. I.

doi:10.1088/0741-3335/53/7/074017

Cited by 10 publications

(7 citation statements)

References 94 publications

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“…(b) Impurity boundary conditions: The heat and particle fluxes on structures during disruptions can liberate sufficient impurities and neutral hydrogen 77,96,97 to be an essential element in the evolution of a disruption. Even a relatively small pulse of energy and particles from the plasma can lead to sufficient impurity radiation near the plasma edge to narrow the current profile and increase the tendency of the magnetic surfaces to break up.…”

Section: Evolution Driven By the Wallsmentioning

confidence: 99%

Theory of tokamak disruptions

Boozer

2012

Physics of Plasmas

133

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Section: Evolution Driven By the Wallsmentioning

confidence: 99%

Theory of tokamak disruptions

Boozer

2012

Physics of Plasmas

133

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“…Several dust generation processes have been suggested [2,7] and the research of dust in fusion devices has been reviewed recently [3,[8][9][10][11][12] including in situ observation with modelling and ex situ post-mortem analyses. The remark must be made that in situ observation of dust events, especially of light-emitting particles with fast cameras, can hardly be correlated with the populations of the different dust types and size distributions observed by post-mortem analyses.…”

Section: Introductionmentioning

confidence: 99%

“…Since the late 1990s particles have been collected in various fusion plasma devices during vents for post-mortem analysis [2,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35], and several attempts have been made to model the behaviour of dust particles in a fusion plasma [3,11,12,[36][37][38][39][40][41][42]. In ASDEX Upgrade (AUG), starting after campaign 1999, the complete transition from a carbon to a full tungsten first wall [43,44] was monitored.…”

Section: Introductionmentioning

confidence: 99%

Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade

et al. 2014

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Abstract.The dust collection and analysis strategy in ASDEX Upgrade (AUG) is described. During five consecutive operation campaigns (2007)(2008)(2009)(2010)(2011), Si collectors were installed, which were supported by filtered vacuum sampling and collection with adhesive tapes in 2009. The outer and inner morphology (e.g. shape) and elemental composition of the collected particles were analysed by scanning electron microscopy. The majority of the ~50000 analysed particles on the Si collectors of campaign 2009 contain tungsten -the plasma-facing material in AUG -and show basically two different types of outer appearance: spheroids and irregularly shaped particles. By far most of the W-dominated spheroids consist of a solid W core, i.e., solidified W droplets. A part of these particles is coated with low Z material; a process which seems to happen presumably in the far scrape off layer plasma. In addition, some conglomerates of B, C, and W appear as spherical particles after their contact with plasma. By far most of the particles classified as B-, C-, and W-dominated irregularly shaped particles consist of the same conglomerate with varying fraction of embedded W in the B-C matrix and some porosity, which can exceed 50%. The fragile structures of many conglomerates confirm the absence of intensive plasma contact. Both the ablation and mobilization of conglomerate material and the production of W droplets are proposed to be triggered by arcing. The size distribution of each dust particle class is best described by a lognormal distribution allowing an extrapolation of the dust volume and surface area. The maximum in this distribution is observed above the resolution limit of 0.28 µm only for the W-dominated spheroids, at around 1 µm. The amount of W-containing dust is extrapolated to be less than 300 mg on the horizontal areas of AUG.

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“…They are relatively long-lived and quasi-coherent structures, whose dynamical properties in the SOL are governed mostly by their size and by the dissipations, both in the bulk plasma and at their contact with the conductive wall of the vessel. See the reviews [8,9]. Blobs are usually studied within the interchange mode paradigm, see the review [8], our earlier papers [6,10] and the references therein.…”

Section: Model Equations For Ftumentioning

confidence: 99%

A self-consistent picture for hyper-velocity metal dust in FTU

2013

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Numerical simulations of the propagation of plasma blobs in the scrape-off layer (SOL) of the Frascati Tokamak Upgrade (FTU) are presented. The maximum distances that a plasma blob may travel in the radial direction are calculated under FTU physical conditions and geometry, taking into account the dissipation due to the presence of dust. It is found that a relatively small amount of nanometre iron dust particles can dissipate blobs before they reach the wall. The amount of dust required is of the same order as, or smaller than, that needed to produce hyper-velocity dust particles, so that a consistent interpretation is reached for experiments in FTU where evidence of the dust impact ionization was reported.

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Multifaceted physics of edge plasma in magnetic fusion devices

Abstract: Recent developments in different areas of edge plasma physics, including plasma transport, atomic physics effects, plasma-wall interactions and other wall-related issues, are highlighted and reviewed.

Cited by 10 publications

References 94 publications

Theory of tokamak disruptions

Theory of tokamak disruptions

Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade

A self-consistent picture for hyper-velocity metal dust in FTU

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