Analysis of the outer divertor hot spot activity in the protection video camera recordings at JET

Aleksander Drenik, JET Contributors, Tommy Ahlgren

Research output: Contribution to journalArticleScientificpeer-review


Hot spots on the divertor tiles at JET result in overestimation of the tile surface temperature which causes unnecessary termination of pulses. However, the appearance of hot spots can also indicate the condition of the divertor tile surfaces. To analyse the behaviour of the hot spots in the outer divertor tiles of JET, a simple image processing algorithm is developed. The algorithm isolates areas of bright pixels in the camera image and compares them to previously identified hot spots. The activity of the hot spots is then linked to values of other signals and parameters in the same time intervals. The operation of the detection algorithm was studied in a limited pulse range with high hot spot activity on the divertor tiles 5, 6 and 7. This allowed us to optimise the values of the controlling parameters. Then, the wider applicability of the method has been demonstrated by the analysis of the hot spot behaviour in a whole experimental campaign.

Original languageEnglish
JournalFusion Engineering and Design
Pages (from-to)115-123
Number of pages9
Publication statusPublished - Feb 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • ITER-like wall
  • Image analysis
  • JET
  • Plasma-wall interaction
  • 114 Physical sciences

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