Development of a novel integrated model GOTRESS+ for predictions and assessment of JT-60SA operation scenarios including the pedestal

Abstract

A novel integrated model GOTRESS+ has been developed, which consists of the iterative transport solver GOTRESS as a kernel of the integrated model, the equilibrium and current profile alignment code ACCOME and the neutral beam heating/current-drive code OFMC. GOTRESS is able to robustly find out an exact solution of the stationary-state transport equations even with a stiff turbulent transport model, taking advantage of global optimization techniques such as a genetic algorithm. GOTRESS+ is then suitable for self-consistently assessing the stationary-state plasma performance of JT-60SA as well as ITER and DEMO or validating their feasibility. Recently GOTRESS+ has been extended to incorporate the in-house EPED1 model exploiting the MHD stability code MARG2D and is now able to predict the plasma profiles even with the pedestal over the entire region from the magnetic axis to the plasma boundary in a self-consistent manner. The two JT-60SA operation scenarios including the ITER-like inductive scenario and the high β fully noninductively current driven scenario have been assessed by GOTRESS+ with the CDBM turbulent transport model and then were found to be feasible with most of the target dimensionless parameters met.

Modification of a machine learning‐based semi‐empirical turbulent transport model for its versatility

“…[35] The details of the integrated simulations with GOTRESS+ are presented in. [19] The integrated simulation for the ITER PFPO-1 plasma has been performed assuming I P = 5.0 MA and B 𝜙 = 1.8 T. The EC heating power is 20 MW, and the main ion species is supposed to be deuterium to compare the results with those shown in. [36] The impurity species is beryllium.…”

“…The new DeKANIS has been constructed with the NN model built in Section 2 and the scaling formula presented in Section 3. We apply DeKANIS to predict a plasma envisioned in the ITER PFPO‐1 phase by performing an integrated simulation with GOTRESS+ [ 19 ] including the edge pedestal region. As the plasmas in this phase are heated by electron cyclotron (EC) resonance, T e / T i >1 is expected, which is not covered by the previous DeKANIS.…”

“…The new DeKANIS with these modifications will be applied to predicting an ITER plasma in the pre-fusion power operation 1 (PFPO-1) phase with the integrated model GOTRESS+. [19] The rest of this paper is organized as follows. In the next section, the datasets for NN training will be expanded to construct the new NN model covering a wider parameter range.…”

“…The new DeKANIS with these modifications will be applied to predicting an ITER plasma in the pre‐fusion power operation 1 (PFPO‐1) phase with the integrated model GOTRESS+. [ 19 ]…”

Completion of JT-60SA construction and contribution to ITER

“…Plasma performance prediction: the plasma prediction in typical operation scenarios is important for the preparation of experiments. To this end, a novel integrated model GOTRESS + has been developed with the steady-state transport solver GOTRESS at its core, together with the QST version of the EPED1 pedestal model based on the MARG2D stability code, which realizes a linear MHD stability analysis not only for the pedestal but also for the core [37]. GOTRESS + was exploited to develop the high-β steady-state scenario as shown in figure 23, where a MHD stable plasma with β N = 4.31 is obtained by the careful control of N-NBs and P-NBs.…”