Abstract Details
Abstracts
Author: Javier Escoto
Requested Type: Poster
Submitted: 2026-03-19 16:12:52
Co-authors: J.L. Velasco, I. Calvo, M. Landreman, F.I. Parra
Contact Info:
Princeton Plasma Physics Laboratory
100 Stellarator Road
Princeton, New Jersey 08540
United States
Abstract Text:
Stellarator magnetic fields must be optimized to achieve the confinement quality required for fusion reactors. In order to exhibit radial neoclassical transport as small as tokamaks, stellarators are typically designed to be approximately omnigenous [1]. Although radial neoclassical transport has traditionally been minimized indirectly by means of figures of merit such as the effective ripple [2], recent developments have enabled to carry out this minimization using accurate calculations of radial neoclassical transport at low collisionality [3]. However, not only neoclassical transport across flux-surfaces is important for stellarator optimization. The bootstrap current modifies the magnetic field and, therefore, needs to be evaluated during the optimization process. In the past, for general geometry, accurate calculations of the bootstrap current were too slow to be included in a stellarator optimization loop.
In this poster we present MONKES [4], a neoclassical code conceived to satisfy the need for fast and accurate calculations of the bootstrap current. By exploiting the tridiagonal structure of the drift-kinetic equation in a Legendre basis, it is possible to obtain accurate calculations of all the monoenergetic transport coefficients [5] at low collisionality using a single core in approximately one minute. These features make MONKES ideally suited for its inclusion in optimization suites for direct optimization of neoclassical transport. Apart from stellarator design, MONKES can find many other applications. For instance, it can be employed for the analysis of experimental discharges and be integrated into predictive transport frameworks.
[1] J.R. Cary and S.G. Shasharina. Phys. Plasmas 4, 3323 (1997).
[2] V.V. Nemov et al. Physics of Plasmas 6, 4622 (1999).
[3] J.L. Velasco et al. Journal of Computational Physics 418, 109512 (2020).
[4] F.J. Escoto et al. Nucl. Fusion 64 076030 (2024).
[5] S.P. Hirshman et al. Physics of Fluids 29, 2951 (1986)
Characterization: 1.0
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