학술논문

Measurement of toroidal variation in conducted heat loads in locked mode induced disruptions on DIII-D.
Document Type
Article
Source
Physics of Plasmas. Oct2018, Vol. 25 Issue 10, pN.PAG-N.PAG. 7p. 1 Diagram, 1 Chart, 6 Graphs.
Subject
*TOROIDAL plasma
*PLASMA gases
*TOKAMAKS
*HEAT losses
*FUSION reactor divertors
*PLASMA physics
Language
ISSN
1070-664X
Abstract
Locked mode disruptions with a controlled toroidal phase are produced in the DIII-D tokamak by locking to large non-axisymmetric applied magnetic perturbations with different toroidal phases. The disruption conducted heat loads are found to reach almost completely the divertor region, possibly due to not only strong inner leg detachment but also plasma motion and limiting on the outer divertor leg shelf. The outer leg conducted heat loads are found to have a significant toroidal variation of order ± 30%, with a dominant n = 1 structure. The heat load phase is shifted from the initial locked mode phase in a way that is approximately consistent with heat loss into the scrape-off layer being enhanced at the mode island O-point outer midplane crossing. These measurements suggest that pre-existing locked modes can affect the conducted heat load structure during the thermal quench by affecting the thermal quench MHD phase. This is consistent with previous MHD simulations which indicated that pre-disruption locked mode structures can persist and survive to some degree through the large thermal quench MHD. This work complements previous work [Shiraki et al., Nucl. Fusion 55, 073029 (2015)] which showed that n = 1 structures in mitigated disruptions can create toroidal variations in the disruption radiated power. [ABSTRACT FROM AUTHOR]