Speaker
Manaure Francisquez
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.1035.pdf
GDB flux-driven turbulence simulations of the
IWL Alcator C-Mod L-mode boundary plasma compared
with experiment and stochastic model
M. Francisquez, B. Zhu, B. Rogers
Dartmouth College, Hanover, NH, USA
Prior to predicting confinement regime transitions in tokamaks one may need an accu-
rate description of L-mode profiles and turbulence properties. These features determine
the heat-flux width upon which wall integrity depends, a topic of major interest for re-
search aid to ITER. To this end our work uses the Global Drift Ballooning (GDB) model [1]
to simulate the Alcator C-Mod edge and contributes support for its use in studying criti-
cal edge phenomena in current and future tokamaks. We carried out 3D electromagnetic
flux-driven two-fluid turbulence simulations of inner wall limited (IWL) C-Mod shots
spanning closed and open flux surfaces [2]. These simulations are compared with gas
puff imaging (GPI) and mirror Langmuir probe (MLP) data, as well as the stochastic
fluctuation model [3], examining global features and statistical properties of turbulent
dynamics. GDB reproduces important qualitative aspects of the C-Mod edge regarding
global density and temperature profiles, within reasonable margins, and though the tur-
bulence statistics of the simulated turbulence follow similar quantitative trends questions
remain about the model’s difficulty in exactly predicting quantities like the autocorrela-
tion time. A proposed breakpoint in the near SOL pressure and the posited separation
between drift and ballooning dynamics it represents are examined. This experimental-
stochastic comparison helps us assess the reliability of GDB as a physics and a predictive
tool for other studies.
[1] B. Zhu, et al., submitted to Comp. Phys. Comm. (2017)
[2] M. Francisquez, et al., Nucl. Fusion 57 (2017) 116049
[3] O. E. Garcia, et al., Phys. Plasmas 23 (2016) 052308
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