scholarly journals Progress on Integrated Neutron Diagnostics for Deuterium Plasma Experiments and Energetic Particle Confinement Studies in the Large Helical Device During the Campaigns from FY2017 to FY2019

2021 ◽  
Vol 16 (0) ◽  
pp. 1102023-1102023
Author(s):  
Kunihiro OGAWA ◽  
Mitsutaka ISOBE ◽  
Masaki OSAKABE
2021 ◽  
Vol 92 (4) ◽  
pp. 043528
Author(s):  
T. M. Kormilitsyn ◽  
S. Yu. Obudovsky ◽  
R. N. Rodionov ◽  
A. V. Pankratenko ◽  
A. S. Dzhurik ◽  
...  

2020 ◽  
Vol 86 (5) ◽  
Author(s):  
A. Bader ◽  
B. J. Faber ◽  
J. C. Schmitt ◽  
D. T. Anderson ◽  
M. Drevlak ◽  
...  

A new optimized quasi-helically symmetric configuration is described that has the desirable properties of improved energetic particle confinement, reduced turbulent transport by three-dimensional shaping and non-resonant divertor capabilities. The configuration presented in this paper is explicitly optimized for quasi-helical symmetry, energetic particle confinement, neoclassical confinement and stability near the axis. Post optimization, the configuration was evaluated for its performance with regard to energetic particle transport, ideal magnetohydrodynamic stability at various values of plasma pressure and ion temperature gradient instability induced turbulent transport. The effects of discrete coils on various confinement figures of merit, including energetic particle confinement, are determined by generating single-filament coils for the configuration. Preliminary divertor analysis shows that coils can be created that do not interfere with expansion of the vessel volume near the regions of outgoing heat flux, thus demonstrating the possibility of operating a non-resonant divertor.


2011 ◽  
Vol 52 (1) ◽  
pp. 013012 ◽  
Author(s):  
K. Tani ◽  
K. Shinohara ◽  
T. Oikawa ◽  
H. Tsutsui ◽  
S. Miyamoto ◽  
...  

1991 ◽  
Vol 19 (2) ◽  
pp. 217-233 ◽  
Author(s):  
Yuji Nakamura ◽  
Masahiro Wakatani ◽  
Jean-Noel Leboeuf ◽  
B. A. Carreras ◽  
N. Dominguez ◽  
...  

2004 ◽  
Vol 75 (10) ◽  
pp. 3601-3603 ◽  
Author(s):  
M. Osakabe ◽  
T. Seki ◽  
Y. Takeiri ◽  
K. Tanaka ◽  
K. Narihara ◽  
...  

2019 ◽  
Vol 14 (0) ◽  
pp. 3402075-3402075 ◽  
Author(s):  
Hideo NUGA ◽  
Ryosuke SEKI ◽  
Kunihiro OGAWA ◽  
Shuji KAMIO ◽  
Yutaka FUJIWARA ◽  
...  

2019 ◽  
Vol 85 (5) ◽  
Author(s):  
Aaron Bader ◽  
M. Drevlak ◽  
D. T. Anderson ◽  
B. J. Faber ◽  
C. C. Hegna ◽  
...  

Stellarator configurations with reactor relevant energetic particle losses are constructed by simultaneously optimizing for quasisymmetry and an analytically derived metric ( $\unicode[STIX]{x1D6E4}_{c}$ ), which attempts to align contours of the second adiabatic invariant, $J_{\Vert }$ with magnetic surfaces. Results show that with this optimization scheme it is possible to generate quasihelically symmetric equilibria on the scale of ARIES-CS which completely eliminate all collisionless alpha particle losses within normalized radius $r/a=0.3$ . We show that the best performance is obtained by reducing losses at the trapped–passing boundary. Energetic particle transport can be improved even when neoclassical transport, as calculated using the metric $\unicode[STIX]{x1D716}_{\text{eff}}$ , is degraded. Several quasihelically symmetric equilibria with different aspect ratios are presented, all with excellent energetic particle confinement.


2021 ◽  
Author(s):  
Frederick Law ◽  
Antoine J Cerfon ◽  
Benjamin Peherstorfer

Abstract In the design of stellarators, energetic particle confinement is a critical point of concern which remains challenging to study from a numerical point of view. Standard Monte Carlo analyses are highly expensive because a large number of particle trajectories need to be integrated over long time scales, and small time steps must be taken to accurately capture the features of the wide variety of trajectories. Even when they are based on guiding center trajectories, as opposed to full-orbit trajectories, these standard Monte Carlo studies are too expensive to be included in most stellarator optimization codes. We present the first multifidelity Monte Carlo scheme for accelerating the estimation of energetic particle confinement in stellarators. Our approach relies on a two-level hierarchy, in which a guiding center model serves as the high-fidelity model, and a data-driven linear interpolant is leveraged as the low-fidelity surrogate model. We apply multifidelity Monte Carlo to the study of energetic particle confinement in a 4-period quasi-helically symmetric stellarator, assessing various metrics of confinement. Stemming from the very high computational efficiency of our surrogate model as well as its sufficient correlation to the high-fidelity model, we obtain speedups of up to 10 with multifidelity Monte Carlo compared to standard Monte Carlo.


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