Transient induced tungsten melting at the Joint European Torus (JET).

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389021%3A_____%2F17%3A00482349" target="_blank" >RIV/61389021:_____/17:00482349 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1088/1402-4896/aa8789" target="_blank" >http://dx.doi.org/10.1088/1402-4896/aa8789</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1402-4896/aa8789" target="_blank" >10.1088/1402-4896/aa8789</a>

Result language

angličtina

Original language name

Transient induced tungsten melting at the Joint European Torus (JET).

Original language description

Melting is one of the major risks associated with tungsten (W) plasma-facing components (PFCs) in tokamaks like JET or ITER. These components are designed such that leading edges and hence excessive plasma heat loads deposited at near normal incidence are avoided. Due to the high stored energies in ITER discharges, shallow surface melting can occur under insufficiently mitigated plasma disruption and so-called edge localised modes-power load transients. A dedicated program was carried out at the JET to study the physics and consequences of W transient melting. Following initial exposures in 2013 (ILW-1) of a W-lamella with leading edge, new experiments have been performed on a sloped surface (15 degrees slope) during the 2015/2016 (ILW-3) campaign. This new experiment allows significantly improved infrared thermography measurements and thus resolved important issue of power loading in the context of the previous leading edge exposures. The new lamella was monitored by local diagnostics: spectroscopy, thermography and high-resolution photography in between discharges. No impact on the main plasma was observed despite a strong increase of the local W source consistent with evaporation. In contrast to the earlier exposure, no droplet emission was observed from the sloped surface. Topological modifications resulting from the melting are clearly visible between discharges on the photographic images. Melt damage can be clearly linked to the infrared measurements: the emissivity drops in zones where melting occurs. In comparison with the previous leading edge experiment, no runaway melt motion is observed, consistent with the hypothesis that the escape of thermionic electrons emitted from the melt zone is largely suppressed in this geometry, where the magnetic field intersects the surface at lower angles than in the case of perpendicular impact on a leading edge.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10300 - Physical sciences

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physica Scripta

ISSN

0031-8949

e-ISSN

—

Volume of the periodical

T170

Issue of the periodical within the volume

December

Country of publishing house

SE - SWEDEN

Number of pages

9

Pages from-to

—

UT code for WoS article

000414120500013

EID of the result in the Scopus database

2-s2.0-85030833385