Bencze 1 charles university in prague, faculty of mathematics and physics, prague, czech republic. An overview of the physical model of the dust in tokamaks code article pdf available in physics of plasmas 174. Shkarofsky, evaluation of multipole moments over the current density in a tokamak with magnetic probes, phys. At present, there are two main codes simulating the interactions of an isolated spherical dust grain with a nonmagnetized plasma e. These dust samples were collected and analyzed because of the importance of dust to safety. Why laser process is suitable for dust removal from tokamaks. Therefore, a series of dust structure characterization studies were performed during past years in tokamaks, and the experiments simulating working conditions in tokamaks were carried out. Simulation of dust statistical characteristics in tokamaks simulation of dust statistical characteristics in tokamaks smirnov, r. The influence of see on the floating potential of tokamak. Dust grain charging in tokamak plasmas semantic scholar. As of 2016, it is the leading candidate for a practical fusion reactor tokamaks were initially conceptualized in the 1950s by. Dust limit management strategy in tokamaks sciencedirect.
Tokamak dust transport the tokamak is the most successful magnetic confinement configuration for fusion, and many tokamaks exist in laboratories across the globe. There are some tokamaks which may not use the iterlike materials but still metal, e. In tokamak plasmas, significant secondary and thermionic electron emis sion can be caused. Insuchsimulationcodes, a plasma background is coupled with a dust model. Tokamak definition is a toroidal device for producing controlled nuclear fusion that involves the confining and heating of a gaseous plasma by means of an electric current and magnetic field. The first step to realize such a cleaning process is the mobilization of the dusts. The tokamak an acronym from the russian words for toroidal magnetic. In situ tunnel microscopy has allowed us to start studying. The modelling of a controlled tungsten dust injection experiment in textor by the dust dynamics code migraine is reported.
Magnetic fields and magnetic diagnostics for tokamak. Dust in tokamaks has been widely investigated 4, but magnetic dust can be mobilized in the vacuum vessel by the external magnetic eld before and during the startup stage of discharges. The results on dust transport in nstx, diiid, and iter tokamaks are presented. Dust observation in the compass tokamak using fast camera m. Please update your bookmarks to go to the domain which has remained unchanged even though the hosting location moved. The code allows tracking of test dust particle in realistic plasma background calculated with the edgeplasma transport code uedge. Reactor iter, dust contamination presents problems for diagnostic integration.
Lecture notes mhd theory of fusion systems nuclear. Modelling and diagnostics of hypervelocity dust particles. It consists of a complex system of magnetic fields that confine the plasma of reactive charged particles in a hollow, doughnutshaped container. Carbon tritide from tokamaks is toxic, radioactive and chemically reactive. Invessel dust and tritium together with acp in primary cooling water circuits safety analysis based on invessel inventories dust level of dust accumulation. Dust has not yet been of a major concern in existing tokamaks mainly because the quantity is small and these devices are not nuclear facilities. An overview of the physical model of the dust in tokamaks code. Figure 5 shows the nssr2 dust size distribution and dust sizes collected in cmod, diiid, tftr, and sirens. E ects of dust on plasma discharges during tokamaks start. Tokamak, device used in nuclearfusion research for magnetic confinement of plasma. Simulation of dust statistical characteristics in tokamaks. Flakedust production will inevitably increase with the increase in duty cycle in nextstep devices with graphite plasma facing components.
Detection of fast dust particles in tokamaks by aerogel. The activity includes studies of dust phenomena in tokamaks, stellarators and zpinches, development of monitoring tools, dust generation theory in reactor conditions, technologies of dust evacuation and control of tokamak operation by dust jets. Diagnostics from both groups are employed in contemporary tokamaks. Comprehensive modeling of dust particle transport in. Since the first introductory account of tokamaks in 1987, when the tokamak had become the predominant device in the attempt to achieve. Plasmamaterial interactions in current tokamaks and their implications for. In this work, the current status of the dust in tokamaks dtoks j. Diagnostics of hypervelocity dust motivation hypervelocity dust impacts do occur in tokamaks during plasma discharges in ftu, the rate of these events is r 102s1 cm2.
Dust observation in the compass tokamak using fast camera. At present the largest is the joint european torus jet located at culham, but a much larger device, the international nextstep fusion tokamak, iter, is currently under construction. The management of dust particles is one of the serious plasma material interaction issues that needs to be resolved before iter can study burning plasmas. Abstract in this work we analyze the size radius distribution function of dust particles in tokamak plasmas during a steady state discharge. The dust may contain tritium, be activated, be chemically toxic, and chemically reactive. Insitu tunnel microscopy has allowed us to start studying. Specifications of 226 machines are given on this site of which perhaps 50 are operating today.
Tokamak dust particle size and surface area measurement. Onjun4 1department of physics, faculty of science, kasetsart university, chatuchak, bangkok 10900, thailand. Diagrams showing temperature of a spherical carbon dust particle at thermal equilibrium in a deuterium plasma with temperature t e t i and with fraction c 1% of carbon impurity ions. R d smirnov et al, modelling of dynamics and transport of carbon dust particles in tokamaks, plasma phys. The tokamak is one of several types of magnetic confinement devices being developed to produce controlled thermonuclear fusion power. Modelling of dynamics and transport of carbon dust. A relation between the radius distribution function of.
This book acts as an introduction to the subject and a basic reference for theory, definitions, equations, and experimental results. Superheating on molten dust in l and hmode operations n. The following mechanisms of dust mobilization have been taken into account. Dust signals are closely correlated with particles observed by a visible ccd camera 82% of dust particles detected are due to disruptions dust signals are correlated with the severity of the disruption data from 481 shots have been anlaysed. Magnetic fields and magnetic diagnostics for tokamak plasmas. Recent studies of dust in tokamaks atomic and molecular data. Wesson, in tokamaks, oxford science publications, clarendon press, oxford, 1987.
Diagnostics of fast dust particles in tokamak edge plasmas. The tokamak a doughnutshaped vacuum chamber surrounded by magnetic coils is the principal tool in controlled fusion research. Recently in ftu 5 the presence of an estimated average dust density of 2 30 10 3 cm 3 before the startup phase was documented. With the high heat output of the future metallic tokamaks, much more metallic dust grains should be produced, the situation of which never occurs. Oct, 2011 the tokamak a doughnutshaped vacuum chamber surrounded by magnetic coils is the principal tool in controlled fusion research. Observations of skeletal microstructures in various types. Gian luca delzanno, xianzhu tang submitted on 15 nov 20 v1, last revised 7 feb 2014 this version, v2. A tokamak a russian acronym for toroidal chamber with axial magnetic field is a fusion device that uses a combination of electromagnets and electric currents to contain plasma, which is used to. An extensive list of current and historic tokamaks from around the world. Iter invessel dust and tritium control implementation.
Mobilization of dust and exfoliation of erosion product. Controlling surface dust in a tokamak sciencedirect. The ineel has analyzed a variety of dust samples from experimental tokamaks. Dustt 23 and dtoks 24, which include dust graincharging,heating,andmotion. Oct 31, 2008 dust production and accumulation present potential safety and operational issues for the iter. Dust transport in the divertor sheath article pdf available in physics of plasmas 212. Dust is produced in tokamaks by the interaction between the plasma and the plasma facing components. Dust in tokamaks can be produced by the disassembly of plasma facing tile surfaces or of plasmagrown codeposited layers under the impact of elms or disruptions, or by the chemical agglomeration of sputtered c n.
Allen 3 1 imperial college, london, uk 2 euratomukaea fusion association, culham science centre, abingdon, uk 3 university college, oxford, uk introduction production of dust particles during tokamak operation is a critical issue for magnetic con. Numerical studies on dust and droplet from tokamak. Also the diagnostic tool 22 can provide metallic dust grains in a chamber. Erosion of material leading to micro particles creation. Its hazard degree, mobilization capability and catalytic efficiency depend on dust particle size and structure. Numerical studies on dust and droplet from tokamak divertor. Characterization and origin of large size dust particles. Indeed, before their collection, they must be moved away from the surface to reduce the surfaceparticle adhesion force. Modelling and diagnostics of hypervelocity dust particles in a tokamak f. Characterisation of carbon dust produced in sputtering. Theory and simulation of dust in tokamak plasmas citeseerx. Gian luca delzanno, xianzhu tang submitted on 15 nov 20. Craters with typical diameters d 20 m and depths d 5 m are produced wall erosion 1 1nm s hypervelocity dust impacts are potentially harmful for fusion.
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