Shear Alfvén stability in a quasi-axisymmetric (QA) beam-target stellarator

POSTER

Abstract

Thea Energy, Inc. plans to build Eos, a quasi-axisymmetric (QA), large-scale, beam-target fusion, stellarator neutron source. Eos has two oppositely directed neutral beam injectors (NBIs) at toroidal angles 0 and 𝜋. Fast ions from neutral beams can drive Alfvén waves in stellarators, as demonstrated previously in W7-AS [1] and TJ-II [2]. Due to its high-beam-pressure, Alfvénic instabilities are likely important in Eos. A workflow using Stellgap [3], FAR3D [4], and SIMSOPT [5] particle tracing to assess the Alfvénic stability of Eos and beam-driven stellarators in general is presented. Stellgap calculates the Eos shear Alfvén continuum. Comparisons between the gap structure of Eos and other QA configurations are given. FAR3D determines the growth rate and frequency of Alfvén eigenmodes. SIMSOPT particle tracing models the fast particle response to Alfvén eigenmodes. The overall Alfvénic stability analysis presented here for Eos can be applied to other beam-driven stellarators.



[1] A. Weller, et al. Phys. Rev. Lett. 72, 1220–1223 (1994).

[2] A.V. Melnikov, et al. Nucl. Fusion. 54, 123002 (2014).

[3] D. A. Spong, et al. Phys. Plasmas. 10 (8): 3217–3224 (2003).

[4] J. Varela, et al. Front. Phys. 12:1422411 (2024).

[5] M. Landreman, et al. J. Open Source Software. 6, 3525 (2021).

*We acknowledge funding through the Simons Foundation collaboration 'Hidden Symmetries and Fusion Energy', Grant No. 601958. We acknowledge funding through the U. S. Department of Energy, under contracts DESC0024630, DE-SC0024548, and DE-AC02-09CH11466.

Presenters

  • Abdullah Syed Hyder

    • Columbia University

Authors

  • Abdullah Syed Hyder

    • Columbia University

  • Elizabeth J Paul

    • Columbia University

  • Alexey Romanovich Knyazev

    • Columbia University

  • Jens Von Der Linden

    • Thea Energy

  • Charles P.S. Swanson

    • Thea Energy

  • Donald A. Spong

    • Oak Ridge National Laboratory