Speaker
J. M. Park
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P5.1096.pdf
Theory-based Scaling of Energy Confinement Time for Future Reactor Design*
J.M. Park1, G. Staebler2, P.B. Snyder2, C.C. Petty2, D.L. Green1, K.J. Law1
1
Oak Ridge National Laboratory, Oak Ridge, TN, USA
2
General Atomics, PO Box 85608, San Diego, CA, USA
A theory-based scaling of thermal energy confinement time has been derived based on TGLF
and EPED in burning plasma conditions for future reactor design. The simulation dataset
consists of a massive number of predictive IPS-FASTRAN [1] simulations, self-consistent
with core transport (TGLF), edge pedestal (EPED), alpha heating, and MHD equilibrium
(EFIT). The DAKOTA-enabled Integrated Plasma Simulator (IPS) framework generates the
multi-dimensional parametric scan with random sampling of major radius (4 < R < 8 m),
aspect ratio (2.5 < R/a < 3.5), elongation (1.5 < k < 2.0), triangularity (0.3 < d < 0.6), toroidal
magnetic field (4 < BT < 8 T), plasma current (3.5 < q95 < 8.5), line average density (0.6 < ne
/nGW < 1), and heating power (20 < Pinj < 150 MW). Each IPS-FASTRAN simulation in the
scan is largely theory-based except a model specification of the heating and plasma current
profiles. A Gaussian form of the heating profile is employed with the ratio of electron and ion
heating as an additional scan parameter (0.0 < Pe/Pi < 1.0) to take into account difference in
the heating and current drive actuators such as neutral beam injection and RF heating. The
model current profile is a combination of the bootstrap current in the edge pedestal
determined by EPED and the core current profile parameterized to make variation of
minimum q (qmin), the minimum q location (rqmin), and the average magnetic shear (q0-qmin) in
the core. For the ITER baseline H-mode type current profile with q0~1.0, the TGLF/EPED
energy confinement time scales as
tTGLF/EPED = 0.098 Ip0.80 BT0.28 ne0.42 P-0.71 R2.1 k0.81 e0.90,
in a dimensionally homogenous form, showing ~ +/-10% difference from the ITER H-mode
confinement scaling of the multi-machine experimental database [2] for the data set
generated in burning plasma condtion. The exponent of the log-linear scaling expression
reveals different dependency on the engineering variables, for example stronger dependency
on BT. Substantial improvement of energy confinement time is predicted for the broader
current profile, tTGLF/EPED ~ (1+0.45rqmin1.2), identifying an optimization path to AT steady-
state reactor. An example of the system code application will be presented.
[1] Park et al, Phys. Plasmas 25, 012506 (2018) [2] McDonald et al, Nucl. Fusion 47, 147 (2007)
*This work was supported in part by US Department of Energy under DE-AC05-00OR22725, DE-FC02-
04ER54698, DE-FG02-95ER54309, and DE-SC0012656
