Publication: VAPOUR SHIELDING OF SOLID TARGETS EXPOSED TO HIGH HEAT FLUX
Дата
2015
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Аннотация
The thickness of a Tungsten monoblocks composing future ITER divertor is supposed to be 8 mm only. Severe erosion caused by a high heat fluxes during transients, such as Type I ELMs and disruptions, therefore is a limiting factor to PFCs lifespan. Thermal loads over the range of Q = 0.5−2 MJ/m2 on the timescale of τ = 0.3− 0.6 ms are expected during Type I ELMs. Even larger heat fluxes, of the order of = − Q 0.5 5 MJ/m2 are expected during thermal quench stage of disruption lasting approximately τ = 1 −3 ms [1]. Under the influence of the extreme heat fluxes serious surface modification and cracking of the Tungsten monoblocks is anticipated [2]. Moreover, melting of a thin surface layer is likely. Melt motion contributes seriously to the material erosion [3]. The other sources of erosion are melt splashing, in form of a droplet ejection, and stationary evaporation [4]. These mechanics lead to a cold dense secondary plasma region formation near the irradiated surface. Intense re-radiation of the incident plasma flow energy in the secondary plasma layer results in a significant reduction of the heat flux reaching the target surface [5]. Accounting for this vapour shielding effect is essential to estimate the surface erosion properly. Predicting the divertor plates lifespan therefore requires deep understanding of all the processes mentioned and their interplay.
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Цитирование
VAPOUR SHIELDING OF SOLID TARGETS EXPOSED TO HIGH HEAT FLUX [Text.] / Pshenov A. A. [и др.] // Взаимодействие ионов с поверхностью «ВИП – 2015»: труды XXII Международной конференции Том 3. - 2015. - С. 298-301