ELECTRODYNAMIC CONTEXT NOTE

Purpose: This note clarifies how the dossier uses solar-wind forcing (HSS) and magnetometer activity (GIMA) in the reconstruction.

A Solar High-Speed Stream (HSS) is treated in this dossier as an external electrodynamic driver capable of increasing magnetosphere–ionosphere coupling. In the reconstruction, the HSS is not “energy delivered to the site,” but a system-level forcing context that can elevate large-scale potentials and current systems in the Earth–ionosphere environment.

In space-physics terms, enhanced solar-wind driving can reorganize current systems and field-aligned coupling between the magnetosphere and ionosphere. Observable consequences can include changes in ionospheric current intensity, geometry (specifically spatial confinement within the auroral oval), and associated magnetic perturbations measured at ground stations. In this dossier, those observables are used in a restricted way:

  1. Reservoir/forcing context (HSS): The HSS is treated as consistent with the existence of a broad external reservoir/driver (\~11:00 UTC onset) that could enable regional coupling conditions (if the forensic constraints motivating an "open system" are upheld).
  2. Activation/gating marker (GIMA H-Component Onset): The coherent onset of a negative H-component bay recorded in the Alaska chain (\~12:15 UTC / 08:15 EDT) is treated as a timing marker consistent with circuit gating / high-conductance onset. It is not treated as a direct calorimetric measure of "energy delivered to the target," but as the start of the "Soft Gate" interval (Phase II) and the subsequent regional charging regime.
  3. Implementation remains a hypothesis: Any claim about the specific "down-coupling" pathway from the ionosphere/upper atmosphere into a localized ground target is presented here as a reconstruction hypothesis that must earn credibility by producing checkable collateral signatures (e.g., Poleward Expansion) and by outperforming Model A under the dossier’s symmetric scoring rules.

Bottom line: Within this dossier’s logic chain, HSS supplies plausible global-scale forcing context and GIMA supplies a candidate timing handle for a transition into a charged/activated interval (08:15–08:46 EDT). The reconstruction then proposes how a localized delivery architecture could have exploited that context to satisfy the cross-report constraints (energy/phase-state, impulse partition, bounded geometry, and selective coupling).