Plasma radiation distribution and radiation loads onto the vessel during transient events in JET

Huber, A.; Pitts, R.A.; Loarte, A.; Philipps, V.; Andrew, P.; Brezinsek, S.; Coad, J. P.; Eich, T.; Fuchs, Julien; Fundamenski, W.; Jachmich, S.; Matthews, G. F.; McCormick, K.; Mertens, Ph.; Rapp, J.; Sergienko, G.; Stamp, M.; Contributors, Jet

doi:10.1016/j.jnucmat.2009.01.219

Cited by 17 publications

(9 citation statements)

References 10 publications

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“…After the runaway loss phase is over, the remaining current in the post-runaway plasma decays on timescales of ∼5 ms. The peak in the plasma radiation at the runaway plateau termination is of much smaller magnitude than during the thermal quench and the initial current quench in the disruption and is poloidally localized to the region where runaways are lost as shown in figure 2, in contrast to the radiation distribution in the current quench where it is distributed over a large volume of the plasma [25].…”

Section: Basic Observations Of Disruptions With Formation Of Runaway ...mentioning

confidence: 96%

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Magnetic energy flows during the current quench and termination of disruptions with runaway current plateau formation in JET and implications for ITER

et al. 2011

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The magnetic energy balance and magnetic energy flows for plasma disruptions in which runaway plateau plasmas are formed and terminated at JET has been analysed and compared with that of runaway-free disruptions. The analysis shows that the energy loss processes during runaway plateau plasma termination are qualitatively different from those of a runaway-free disruption because of the pre-existence of a runaway population in the first case. As a consequence, a significant fraction of the runaway plateau plasma magnetic energy is directly converted into runaway electron kinetic energy during the runaway plateau termination phase. This leads to the fluxes being deposited by runaway electrons onto in-vessel components during the termination of runaway plateaus to be significantly larger than those expected from the initial kinetic energy of the runaway electrons in the runaway plateau plasma.

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Section: Basic Observations Of Disruptions With Formation Of Runaway ...mentioning

confidence: 96%

“…Figure25. Simulation of the termination of a JET runaway plateau in which runaways are lost in a series of events over an extended period, from hard x-ray and photoneutron measurements.…”

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confidence: 99%

Magnetic energy flows during the current quench and termination of disruptions with runaway current plateau formation in JET and implications for ITER

et al. 2011

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“…Moreover, the deposition in the outer leg has different composition with a significant fraction of beryllium, implying different structural properties with respect to layers in the inner divertor [28]. Higher atom and molecule carbon light emission [29] and radiative energy losses [30] in the inner divertor are also evidence for the asymmetry observed in the deposition between the inner and outer divertor legs. Laboratory investigations have furthermore demonstrated that hydrogenated carbon layers are more sensitive to thermal loads than bare graphite due to different structural properties [31].…”

Section: Surface Layers and Elm-induced Enhanced Erosionmentioning

confidence: 99%

“…The additional source of carbon can significantly change the balance between gross erosion and gross deposition in the outer divertor, thus changing the net-behaviour of the outer QMB from erosion to deposition dominated. If the release of dust particles is the cause of the ELM-induced enhanced erosion of the inner target, it is conceivable that these clusters can be transported line-of-sight towards the outer divertor even through the outer SOL [30].…”

Section: Influence Of Magnetic Field and Divertor Geometry On Erosionmentioning

confidence: 99%

Dynamics of erosion and deposition in tokamaks

Kreter

Brezinsek

Coad

et al. 2009

Journal of Nuclear Materials

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In recent years, a general qualitative understanding has been reached about the major pathways of material migration in divertor tokamaks. Main chamber wall components have been identified as the major source of material erosion. The eroded material is transported by scrape-off layer flows, in the case of the ion B×∇B drift pointing towards the X-point, predominately towards the inner divertor leg, where it is deposited in the form of amorphous layers. On JET, where carbon is the main plasma-facing material, it has been found that the presence of deposited carbon rich layers determines the dynamic characteristics of further redistribution of carbon, in particular towards remote areas. The transport from the strike point to the deposition location is mainly line-of-sight. The amount of eroded carbon depends on the surface type, with lower rates for the bare CFC and higher rates for deposited layers. The erosion rates in the inner divertor increase non-linearly with increasing ELM energies.

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“…It is well known that impurity penetration into plasma can contribute to fuel dilution and radiation enhancement. With impurities accumulating in the core, the radiation losses can lead to a significant degradation of the plasma confinement and even plasma collapse . Therefore, evaluating the influence of different impurities for the plasma performance is important to understand the plasma operations in EAST.…”

Section: Introduction and Physical Modelmentioning

confidence: 99%

Simulation of impurity behaviour in Experimental Advanced Superconducting Tokamak L‐mode discharges with the integrated COREDIV code

Xie

Zagórski

Ding

et al. 2018

Contributions to Plasma Physics

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The self‐consistent COREDIV code has been used to simulate the Experimental Advanced Superconducting Tokamak (EAST) L‐mode discharges of upper and lower single null configurations operated with tungsten and carbon divertors, respectively. In the simulations, a uniform lithium injection (and, in addition, a C injection for W divertor) from the wall is assumed, and calculations are performed for different diffusion coefficients in the Scrape‐Off Layer (SOL) region. Simulations demonstrate that, in the case with C target, higher lithium flux leads to lower sputtered carbon flux because of the lower particle flux to divertor due to the plasma dilution by lithium. For the case of tungsten target, lithium has almost no influence on plasma parameters. Carbon seeding first leads to higher W concentrations and then to saturated W afterwards. The effect of a prompt re‐deposition process is moderate due to the self‐regulated increase of plasma temperature at the target through tungsten radiation in the core plasma. The simulations can well reproduce the experimental measurements such as plasma density and temperature profiles in the core region, Zeff, total radiation loss and radiation profiles, and electron density and temperature profiles along divertor target.

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Plasma radiation distribution and radiation loads onto the vessel during transient events in JET

Cited by 17 publications

References 10 publications

Magnetic energy flows during the current quench and termination of disruptions with runaway current plateau formation in JET and implications for ITER

Magnetic energy flows during the current quench and termination of disruptions with runaway current plateau formation in JET and implications for ITER

Dynamics of erosion and deposition in tokamaks

Simulation of impurity behaviour in Experimental Advanced Superconducting Tokamak L‐mode discharges with the integrated COREDIV code

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