Speaker
Evgenii Kiselev
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.1104.pdf
Thermal energy confinement time scaling with Ip and BT in Globus-M
H-mode.
E.O. Kiselev1, M.I. Patrov1, G.S. Kurskiev1, N.N. Bakharev1, V.K. Gusev1, A.Yu. Telnova1,
N A Khromov1, I.V. Miroshnikov1, Yu.V. Petrov1, N.V. Sakharov1, V.B. Minaev1, A D
Sladkomedova1, P.B. Shchegolev1, V.V. Solokha1, V A Tokarev1, S.Yu. Tolstyakov1
1
Ioffe Institute, St. Petersburg, Russia Federation
The presentation is devoted to the thermal energy confinement study at the compact
spherical tokamak Globus-M. Globus-M had major radius R = 0.36 m and minor radius a =
0.24 m (R/a ~ 1.5). The lower-null magnetic configuration is characterized by moderate
elongation k~1.7 and triangularity δ~0.35. Special feature of the Globus-M tokamak is the
extremely high input heating power density: ~0.6 MW/m3 in pure ohmic heating (OH) and
~2.5 MW/m3 under auxiliary heating by neutral beam injection (NBI). The range of
temperatures achieved in Globus-M is = 0.2 – 0.4 keV that leads to higher values of
collisionality ν*=0.03-0.4 and normalized ion gyroradius ρ*~ 0.02-0.04 than in MAST and
NSTX. The present study was performed in both OH and NBI heated H-mode plasmas.
H-mode is the usual operational mode in Globus-M at moderate density range ne>2-2.5∙1019
m-3. The regression fit of the database indicates strong τE dependence on both plasma current
Ip and toroidal magnetic field BT, while the dependence on ne and absorbed power was
similar to the conventional scaling IPB98(y,2). The original technique for calculating the
absorbed power using both NUBEAM [1] and 3d fast-ion tracking algorithm [2] is discussed.
Obtained profiles of the absorbed power were used to estimate electron and ion heat
diffusivity using ASTRA simulation. It was found that the electron heat diffusivity is
strongly affected by the plasma current and the toroidal magnetic field. The BTτE dependence
on ν* is found be similar to the one in NSTX and MAST, while q dependence is stronger than
on MAST, but weaker than in ITER scaling.
1. A. Pankin et al., “The tokamak Monte Carlo fast ion module NUBEAM in the National
Transport Code Collaboration library”, Comp. Phys. Comm. 159 (2004) 157.
2. Bakharev N.N. et al., Fast particle behaviour in the Globus-M spherical tokamak
// Nucl. Fusion – 2015. – Т. 55 – 55043023.
