Speaker
Description
See full abstract here:
http://ocs.ciemat.es/EPS2019ABS/pdf/P5.1017.pdf
I-mode is a naturally ELM-free improved confinement regime which exhibits high energy confinement and a temperature pedestal, but low particle confinement and a density profile similar to L-mode [1]. The weakly coherent mode (WCM) occurs in the pedestal region of Imode plasmas at both ASDEX Upgrade (AUG) and Alcator C-Mod, but the role of the WCM in particle and heat transport remains an open question. In this work, temperature fluctuations in the pedestal of I-mode plasmas are studied through correlation electron cyclotron emission (CECE) at AUG and C-Mod. The electron temperature fluctuation level of the WCM has been measured in C-Mod at 1-2% [2] and in AUG at 2.3% [3]. The optical depth of some CECE measurements at AUG is marginal and therefore the contribution of density fluctuations is studied as part of this work. In addition, a finite phase between density and temperature fluctuations (nT phase) has been observed at AUG using a reflectometer along the same line of sight as the CECE system. Comparison between the two devices and nT phase observations may provide insight into the effect of the edge fluctuations on density and temperature transport.
This work is supported by the EUROfusion Consortium (No 633053), and by US DoE under Grants DE-SC0006419, DE-FC02-99ER54512-CMOD, and DE- SC0017381.
[1] D.G. Whyte et al, Nucl. Fusion 50 (2010) 105005
[2] A.E. White et al., Nucl. Fusion 51 (2011) 1130005
[3] T. Happel et al., Nuclear Materials and Energy 18 (2019) 159-165
