Replication Data for: Vertical Stability at High Elongation: Displacement Growth Rates, Control-Coil Authority, and VDE Avoidance for a Compact Spherical-Tokamak Breeder
Year: 2026
Type: dataset
Abstract: Replication data for the paper Vertical Stability at High Elongation: Displacement Growth Rates, Control-Coil Authority, and VDE Avoidance for a Compact Spherical-Tokamak Breeder (Kronos Fusion Energy 2026 Publication Series, paper 2.8), published at doi:10.5281/zenodo.22645834. Abstract of the paper. Elongation buys confinement in a compact machine, and it is not optional: the Hyperion spherical-tokamak breeder holds I_p=9.66 at elongation κ=2.0 with negative triangularity δ=-0.30, aspect ratio A=2.5 and major radius =1.20. The price of that elongation is a passive axisymmetric vertical instability, and in a spherical tokamak the instability is fast. We pose the vertical-control problem formally, from the massless rigid-displacement force balance through the passive-vessel circuit to a proportional– derivative (PD) feedback loop closed on the poloidal-field (PF) coils, and we solve it on the canonical free-boundary equilibrium reconstructed by a GPU-accelerated Grad–Shafranov solver. A single mechanistic result organises the analysis: the normalised growth rate obeys τ_w=/(1-), where is the destabilising-to-wall coupling and 1 is the ideal wall limit. At κ=2.0 the vessel vertical-mode wall time is τ_w=11.9 and τ_w=8.05, so =0.890, =677 and the growth time is 1.48 — spherical-tokamak-typical (NSTX-class). A PD controller on the PF coils arrests the mode: a direct eigenvalue solve of the closed-loop system places a fast pole at -964 (faster than the open-loop growth) and a slow resistive-relaxation pole at -14; the stabilising proportional gain threshold is K_p^*=30302 and the damping threshold is K_d^*≈1156. From a 5 disturbance the excursion peaks at only 8.1 at t≈3.54 and reverses, requiring a PF converter of 49 (10.1, 4.9, 5.0). What this dataset contains data/key_values.csv and data/anchors.json: the frozen design-point values quoted in the paper (symbol, value, unit, provenance), in machine-readable form. data/verification.csv: the validator gates the paper cites, each with its verdict and a link to a live recompute page. figures/: the figures from the paper, as vector PDF, with an inventory. vertical-stability-at-high-elongation-displacement-grow.data-methods.pdf: methods, the computational codes used, and the full value table. data/data_dictionary.md: column definitions. Every value is a frozen design-point number that is independently re-run and recorded in the Kronos Physics De-Risking Register (doi:10.5281/zenodo.22645689). The paper itself is not duplicated here; read it at the DOI above.
Source: Harvard Dataverse
DOI: 10.7910/dvn/png1im
Author: Ford, P I
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214654181