Abstract Details
Abstracts
Author: Gabriel S. Woodbury Saudeau
Requested Type: Consider for Invited
Submitted: 2026-03-06 16:49:44
Co-authors: M. Cianciosa, D. A. Maurer, A. S. Ware
Contact Info:
Auburn University
380 Duncan Dr.
Auburn, AL 36849
US
Abstract Text:
The stellarator concept has many beneficial properties that make it an attractive choice for a future fusion power plant. Playing a notable role in successful optimization of stellarators are 3D MHD equilibrium calculations. Codes such as VMEC and DESC, employing the assumption of closed nested flux surfaces, are routinely used for this task. It is well known that 3D MHD equilibria are composed of a mixture of good surfaces, magnetic islands and field line chaos which is not represented by the closed nested flux surface assumption. We address this important issue by using SIESTA, which has the capability of modeling these effects in a 3D MHD equilibrium. SIESTA requires a user-inputted value for the magnitude of the resonant perturbation which forms the island. As such, a better understanding of this input parameter is needed to understand the island size as calculated. To quantify the perturbation's effect on SIESTA magnetic islands, we have modeled m=2, n=1 islands from two Compact Toroidal Hybrid (CTH) discharge equilibrium reconstructions. We have implemented an algorithm to locate both O- and X-points of these magnetic islands and used the Cary-Hanson method to calculate the magnetic island size for varying perturbation magnitudes. Typically, modeling islands whose toroidal mode number is not a multiple of the device’s number of field periods is cumbersome. Recent developments in SIESTA which have made this a tractable problem will be elaborated on. Also, a novel method for interpolating the magnetic field while keeping its divergence-free nature within the code will be discussed.
Characterization: 4.0
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