Speaker
Description
See the full abstract here http://ocs.ciemat.es/EPS2019ABS/pdf/I4.105.pdf
Developing a disruption & runaway electron (RE) mitigation strategy that robustly scales to ITER and beyond is a major challenge. The dynamics is governed by a complex interplay of effects such as the atomic physics and penetration of the high-Z material injected for mitigation, quench dynamics (MHD), kinetic physics, and quantum mechanics. The EUROfusion consortium is executing a coordinated research program to better understand the generation [1,2], control [3] and mitigation [4] of disruption-born REs following massive material injection.
RE studies on ASDEX Upgrade and TCV are carried out using massive gas injection (MGI) of neon, argon and krypton. The injection of high-Z materials mixed with deuterium is a promising mitigation strategy for ITER. A 1:4 argon-deuterium mixture has prevented RE beam formation in the commonly used RE scenario on ASDEX Upgrade. TCV demonstrated RE beam control up to a pre-disruption elongation of k~1.5. Our results indicate that increasing elongation has no significant impact on RE physics and the main challenge is position control.
The scaling of the initial runaway current on plasma- and injection parameters, as well as the subsequent dissipation is analysed using 1D disruption-runaway simulations [5,6] along with state-of-the-art full-f kinetic models7. The high-Z dissipation model [7] was validated using experimental data from multiple European tokamaks. Full-f kinetic simulations were carried out for the first time for the complete duration of the thermal & current quench. These simulations show that an abrupt delivery of high-Z material (e.g. executed by SPI) is expected to significantly decrease the RE generation rate compared to slower injections methods (such as MGI).
References
[1] G. PAUTASSO ET AL. Plasma Physics and Controlled Fusion, 59 (1):014046 (2017).
[2] J. MLYNAR ET AL. Plasma Physics and Controlled Fusion, 61 (1):014010 (2019).
[3] D. CARNEVALE ET AL. Plasma Physics and Controlled Fusion, 61 (1):014036 (2018).
[4] G. PAPP ET AL. IAEA-FEC, IAEA-CN-234-0502:EX/9 (2016).
[5] G. PAPP ET AL. Nuclear Fusion, 53 (12):123017 (2013).
[6] E. FABLE ET AL. Nuclear Fusion, 56 (2):026012 (2016).
[7] L. HESSLOW ET AL. Plasma Physics and Controlled Fusion, 60 (7):074010 (2018).
