DIS Scientific & Technical Memorandum 55/2/00: Ball and Bead Lightning

This document, titled 'Working Paper No. 2: Ball and Bead Lightning' and issued by the DIS on February 1, 2000, provides a technical assessment of ball and bead lightning as a potential explanation for Unidentified Aerial Phenomena (UAP) reports. The paper reviews the nature of these phenomena, noting that they have been investigated scientifically for 200-300 years. It defines ball lightning as a luminous globe that can persist for up to two hours after a storm, while bead lightning is described as a residue of cloud-to-cloud or cloud-to-surface lightning strokes. The document details the physical characteristics of these phenomena, including their varied shapes—such as globes, rods, and torus structures—and their reported sizes, which range from a few centimetres to 15 metres. The paper highlights the complex motion attributes of these phenomena, including jumping, darting, spinning, and hovering, and notes that they can move against the wind or be associated with vortices. A significant portion of the document is dedicated to the potential effects of these phenomena on humans and equipment, specifically focusing on electromagnetic (EM) radiation, thermal effects, and nerve stimulation. It includes detailed tables and figures illustrating human effects thresholds, near-field distances, and the distribution of absorbed radiation. The assessment concludes that because ball and bead lightning can occur in various weather conditions—including clear skies—and produce visual and auditory effects similar to those reported in UAP sightings, they are a viable candidate for explaining many such events. The document emphasizes that while there is no evidence of cumulative effects or long-term after-effects, the potential for short-term physiological and neurological impacts exists due to near-field coupling and EM radiation.