@article{9018,
  author = {U. Sheikh and J. Decker and M. Hoppe and M. Pedrini and B. Sieglin and L. Simons and J.A. Cazabonne and J. Caloud and J. Cerovsky and T. Wijkamp and S. Coda and C. Colandrea and A. Dal Molin and B. Duval and O. Ficker and M. Griener and G. Papp and G. Pautasso and C. Paz-Soldan and C. Reux and E. Tomesova and ASDEX Upgrade Team and TCV team and MST1 Team},
  title = {Benign termination of runaway electron beams on ASDEX Upgrade and TCV},
  abstract = {This paper discusses the development of a benign termination scenario for runaway electron (RE) beams on ASDEX Upgrade and TCV. A systematic study revealed that a low electron density (ne) companion plasma was required to achieve a large MHD instability, which expelled the confined REs over a large wetted area and allowed for the conversion of magnetic energy to radiation. Control of the companion plasma ne was achieved via neutral pressure regulation and was agnostic to material injection method. The neutral pressure required for recombination was found to be dependent on impurity species, quantity and RE current. On TCV, ne increased at neutral pressures above 1 Pa, indicating that higher collisionality between the REs and neutrals may lead to an upper pressure limit. The conversion of magnetic energy to radiated energy was measured on both machines and a decrease in efficiency was observed at high neutral pressure on TCV. The benign termination technique was able to prevent any significant increase in maximum heat flux on AUG from 200 to 600 kA of RE current, highlighting the ability of this approach to handle fully formed RE beams.},
  year = {2024},
  journal = {Plasma Physics and Controlled Fusion},
  volume = {66},
  pages = {035003},
  doi = {10.1088/1361-6587/ad1e31},
}