Overview of Runaway Electron Control and Mitigation Experiments on Tore Supra and Lessons Learned in View of ITER

F. Saint-Laurent, G. Martin, T. Alarcon, A. Le Luyer, P. B. Parks, P. Pastor, S. Putvinski, C. Reux, J. Bucalossi, S. Bremond, P.H. Moreau
2013 Fusion science and technology  
Runaway electrons (RE) generated during disruption are identified as a major issue for ITER and reactor-size tokamaks. A seed of decoupled electrons is produced in the plasma core at thermal quench of the disruption when the current profile flattens due to high MHD activity. These RE are then accelerated by the toroidal electric field associated to the plasma current quench (CQ) up to relativistic energy. They initiate second RE generation during current quench (CQ) due to the avalanching
more » ... s, leading to a multiplication of these relativistic electrons. The impact of RE on the first wall is well localized due to their very small pitch angle. The energy deposition may be huge and plasma facing components (PFC) damages are often reported. Mitigation techniques are thus mandatory to suppress RE formation or/and reduce their heat loads. Two ways are explored on Tore Supra: -Suppress the RE beam formation and avalanche amplification by multiple gas jet injections at (CQ). -Control the RE beam when it is formed and increase the collisionnality to slow-down relativistic electrons.
doi:10.13182/fst13-a24090 fatcat:twsftilvhzdxvksuevepocb33e