The Decisive Test for the GACP Framework: A Universal Dual-Observable Protocol to Confirm or Falsify a Geophysically Anchored Coherent Plasmoid as the Source of Recurrent Anomalous Luminous Phenomena

The Hessdalen valley (Norway, 62.8°N) has exhibited persistent anomalous luminous phenomena for decades, with 15–20 events per week recorded during the 1983–1985 instrumented campaign. Despite continuous automatic monitoring since 1998, no physical explanation has achieved scientific consensus. The Geophysically Anchored Coherent Plasmoid (GACP) framework proposes that the lights are Bennett-pinch plasma structures sustained by electrical currents originating in the valley's sulphide-rich bedrock. We define a dual-observable protocol comprising two logically independent decisive tests — applicable to any single Hessdalen luminous event using instruments already within reach of Project Hessdalen — that imposes constraints individually inconsistent with the predictions of all eight competing models and provides strong evidence for, or falsifies, a geophysically anchored subsurface current source. The protocol is physically universal and applicable at any site worldwide where recurrent anomalous luminous phenomena co-occur with confirmed geophysical conditions C1 (conductive substrate), C2 (stress-concentrating geology), and C3 (seasonal or hydraulic activity).