Relativistic-microwave theory of ball lightning

Abstract

Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics.

Ball lightning: a Renaissance account from Zafra (Spain)

“…Curiously, the physics of ball lightning is far more complicated than it might seem, and there is still no single theory that can successfully explain the variety of characteristics that ball lightning shows. One can consult recent articles by Wu (2016), Stephan et al (2016), and Bychkova et al (2016).…”

Rare, anomalous non‐transient lights associated with cumulonimbus clouds

“…A paper by H.‐C. Wu () provides a comprehensive theory for the production of ball lightning, accounting for its observed properties and behaviour. He shows that X‐ray bursts occur at the steps of the leader stroke of a lightning flash as it nears the end of its travel, as is also seen in laboratory experiments.…”

Origin of transionospheric pulse pairs

“…Regarding the coherent transition radiation, the electron bunch is assumed to have a Gaussian profile , where n b 0 is the peak density and σ t and σ l are the characteristic radii in the transverse and longitudinal directions, respectively. Simulation [ Wu , ] shows that the far‐field transition radiation is a linearly polarized bipolar pulse.…”

“…The radiation intensity can be calculated by , where T ≈7.5 σ l / c is the radiation duration [ Wu , ] and H is the satellite altitude. Figure b displays the radiation intensity at the emission peak versus k 0 for σ l =0.2 m, N = 5×10 11 , and H = 800 km [ Holden et al , ; Jacobson et al , ].…”