TY - JOUR
T1 - Resistive MHD simulation of edge-localized-modes for double-null discharges in the MAST device
AU - Pamela, S.J.P.
AU - Huijsmans, G.T.A.
AU - Kirk, A.
AU - Chapman, I.T.
AU - Harrison, J.R.
AU - Scannell, R.
AU - Thornton, A.J.
AU - Becoulet, M.
AU - Orain, F.
PY - 2013/9/1
Y1 - 2013/9/1
N2 - Recent development of the nonlinear magneto hydrodynamic (MHD) code
JOREK has enabled the alignment of its two-dimensional finite-element
grid along poloidal flux surfaces for double-null Grad-Shafranov
equilibria. In previous works with the JOREK code, only single X-point
plasmas were studied. The fast-camera diagnostic on MAST, which gives a
global view of the pedestal filamentation during an ELM crash, clearly
shows filaments travelling far into the scrape-off layer, as far as the
first wall. Simulation of such a filament dynamics in MAST double-null
plasmas is presented here and compared with experimental observations.
In addition to direct comparison with the fast-camera images, general
aspects of filaments are studied, such as their radial speed and
composition. A qualitative validation of simulations is carried out
against other diagnostics, such as the Thomson-scattering profiles or
the infra-red camera images. Simulations are found to reproduce
experimental edge localized modes in a reasonable manner, with similar
energy losses and divertor heat-flux profiles. However, the MHD model
used for those simulations is a reduced MHD model, which is likely
approaching the limit of its applicability for the MAST device. Also,
the absence of diamagnetic drift terms in the present MHD model results
in nonlinear simulations being dominated by the highest mode number, and
thus coupling with lower mode numbers is not observed.
AB - Recent development of the nonlinear magneto hydrodynamic (MHD) code
JOREK has enabled the alignment of its two-dimensional finite-element
grid along poloidal flux surfaces for double-null Grad-Shafranov
equilibria. In previous works with the JOREK code, only single X-point
plasmas were studied. The fast-camera diagnostic on MAST, which gives a
global view of the pedestal filamentation during an ELM crash, clearly
shows filaments travelling far into the scrape-off layer, as far as the
first wall. Simulation of such a filament dynamics in MAST double-null
plasmas is presented here and compared with experimental observations.
In addition to direct comparison with the fast-camera images, general
aspects of filaments are studied, such as their radial speed and
composition. A qualitative validation of simulations is carried out
against other diagnostics, such as the Thomson-scattering profiles or
the infra-red camera images. Simulations are found to reproduce
experimental edge localized modes in a reasonable manner, with similar
energy losses and divertor heat-flux profiles. However, the MHD model
used for those simulations is a reduced MHD model, which is likely
approaching the limit of its applicability for the MAST device. Also,
the absence of diamagnetic drift terms in the present MHD model results
in nonlinear simulations being dominated by the highest mode number, and
thus coupling with lower mode numbers is not observed.
U2 - 10.1088/0741-3335/55/9/095001
DO - 10.1088/0741-3335/55/9/095001
M3 - Article
SN - 0741-3335
VL - 55
SP - 95001
JO - Plasma Physics and Controlled Fusion
JF - Plasma Physics and Controlled Fusion
IS - 9
ER -