Full-orbit and drift calculations of fusion product losses due to explosive fishbones on JET

JET Contributors

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Fishbones are ubiquitous in high-performance JET plasmas and are typically considered to be unimportant for scenario design. However, during recent high-performance hybrid scenario experiments, sporadic and explosive fishbone oscillations with sawtooth reconnection were observed coinciding with reduced performance and a main chamber hotspot. Fast ion loss diagnostics showed fusion products ejected from the plasma by the fishbones. We present calculations of the perturbed motion of non-resonant fusion products in the presence of fishbones assuming a fixed linear mode structure and frequency. Using careful reconstruction of the equilibrium and measurements of the perturbation, we show that the measured fishbone spatial structure in these experiments can be well modelled as a linear MHD internal kink mode. Both drift and full-orbit calculations predict losses of fusion products at the same location of the observed hotspot, however the calculated energy content of those losses is negligible and cannot be contributing significantly. The fast ions responsible for the hotspot and the reason for their loss both remain unexplained.

Original languageEnglish
Article number016004
JournalNuclear Fusion
Volume59
Issue number1
DOIs
StatePublished - 2019

Bibliographical note

Publisher Copyright:
© EURATOM 2018.

Keywords

  • JET
  • fast particles
  • fishbone
  • fusion products
  • instability
  • losses
  • sawteeth

Fingerprint

Dive into the research topics of 'Full-orbit and drift calculations of fusion product losses due to explosive fishbones on JET'. Together they form a unique fingerprint.

Cite this