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arXiv · 2510.07042

Experimental Results from Early Non-Planar NI-HTS Magnet Prototypes for the Columbia Stellarator eXperiment (CSX)

D. Schmeling·M. Russo·B. T. Gebreamlak·T. J. Kiker·A. R. Skrypek·A. R. Hightower·J. Xue·S. Chen·S. Sohaib·C. Martinez·K. F. Richardson·L. Filor·S. Komatsu·L. Liu·C. Paz-Soldan
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Abstract

The Columbia Stellarator eXperiment (CSX) is an upgrade of the Columbia Non-neutral Torus (CNT) that aims to demonstrate a university-scale, quasi-axisymmetric stellarator using high-temperature superconducting (HTS) technology at an on-axis magnetic field target of 0.5 T. Due to the strain sensitivity of ReBCO (Rare-earth Barium Copper Oxides), adapting it to non-planar stellarator geometries requires new winding, structural, and cooling strategies. We report on the results of a staged prototype program (P1, P2, P3) employing 3D-printed, sectional aluminum coil frames with winding channels, gimballed constant-tension winding mechanics, and solder potting for radial current redistribution and passive quench mitigation. The first prototype, P1 (planar elliptical, double-pancake) tested additive manufacture, sectional joining and baseline winding, achieving predicted fields at 77 K. P2 (non-planar, higher strain) was wound to 42 turns, energized at 30-40 K to produce expected magnetic fields, and studied thermal gradients and resistance at up to 4.5 kAt. Design evolution in P3 introduces concave geometry with dual double-pancakes, 200 turns, and approaches the 70 kAt target at 20 K. In parallel, sub-microhm lap joints have been developed. Together, these results de-risk manufacturing, cooling interfaces, quench management, and diagnostics, paving the way for full-size non-planar HTS stellarator coils for CSX.

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D. Schmeling, M. Russo, B. T. Gebreamlak, T. J. Kiker, A. R. Skrypek, A. R. Hightower, J. Xue, S. Chen, S. Sohaib, C. Martinez, K. F. Richardson, L. Filor, S. Komatsu, L. Liu, C. Paz-Soldan. 2025-10-08. Experimental Results from Early Non-Planar NI-HTS Magnet Prototypes for the Columbia Stellarator eXperiment (CSX). https://doi.org/10.1109/tps.2026.3681798

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