Thunderstorm neutrons

Abstract

To assess the current state of studies of nuclear reactions in thunderstorms, observational data are reviewed on the neutron flux enhancement in thunderclouds and during thunderstorms related to photonuclear reactions because of the bremsstrahlung of the avalanches of high-energy runaway electrons that can develop in thunderstorm electric fields. Selecting thunderstorm neutrons is a challenging problem, since detectors are affected by a mixed field of various penetrating radiations that also includes, apart from neutrons, primary high-energy electrons and their bremsstrahlung. Special attention is given to the discovery of the electron–positron annihilation line with the photon energy of 0.511 MeV in a thundercloud and on Earth’s surface during thunderstorms, providing trustworthy evidence of neutron production by thunderstorms and the photonuclear origin of thunderstorm neutrons. The consequences of this discovery are discussed. “New is a carefully forgotten old.” Favorite proverb of Dr L V Tarasova from VNIIEF, who was the first to detect high-energy runaway electrons and their bremsstrahlung in electric discharges in the open atmosphere [1, 2].

Generation Possibility of Gamma‐Ray Glows Induced by Photonuclear Reactions

“…Another photonuclear effect is its unstable byproducts confirmed by Babich (2017a, 2017b, 2019a); Dwyer et al. (2015); Enoto et al.…”

“…High‐energy atmospheric phenomena (HEAP) (Babich, 2003), although the late discovery with terrestrial gamma‐ray flashes (TGFs: Fishman et al., 1994), have been studied since much earlier as in Wilson (1924, 1925); Libby and Lukens (1973). Different HEAP have been observed over the decades as; spatial distribution and energy spectrum of TGFs (Briggs et al., 2010; Smith et al., 2005; Tavani et al., 2011), particle production—in particular neutrons (Babich et al., 2007; Bratolyubova‐Tsulukidze et al., 2004; Chilingarian et al., 2012a; Martin & Alves, 2010; Rutjes & Ebert, 2017; Shah et al., 1985; Shyam & Kaushik, 1999; Chilingarian et al., 2012b) with the detections reviewed by Babich (2019a), as well as extended gamma‐ray emissions so‐called gamma‐ray glows, thunderstorm ground enhancements (TGEs) or long bursts (Chilingarian, 2013; Kelley et al., 2015; Torii et al., 2002; Tsuchiya et al., 2007, 2012; Wada et al., 2019). Although Libby and Lukens (1973) thought the neutron production as a result from nuclear fusion, photonuclear reactions has been proved to be the generation mechanism (Babich, 2006; Babich et al., 2007; Babich & Roussel‐Dupré, 2007).…”

The prolonged gamma ray enhancement and the short radiation burst events observed in thunderstorms at Tien Shan

“…Possible source of positrons at thunderstorm time can be either electromagnetic interaction of accelerated runaway particles, as suggested by , or β + decay of short living radioactive nuclei which arise under influence of gamma rays from the developing electronphoton avalanche due to the mechanism of photonuclear interaction, as it was discussed e.g. in Enoto et al (2017); Babich (2019). Hence, investigation of the energy and temporal characteristics of positron flux helps to shed light on various features of atmospheric electric discharge.…”

“…This effect is due to the high energy bremsstrahlung radiation emitted at muon passages, with subsequent neutron production in photonuclear reaction of resulting gamma rays, to direct nuclear interactions of the muonic cosmic ray component, and to the µ − -capture mechanism. As well, the photonuclear interaction channel ensures detection of the high energy ( 10 MeV) gamma rays, electrons and positrons by the monitor, thou with a probability ∼(10-30) times below the efficiency of hadron registration: Tsuchiya et al (2012); Babich and Roussel-Dupré (2007); Babich et al (2013aBabich et al ( , 2014; Teruaki et al (2017); Babich (2019).…”

Atmospheric Electron Spatial Range Extended by Thundercloud Electric Field Below the Relativistic Runaway Electron Avalanche Threshold

“…(1994) discovered Terrestrial Gamma ray Flashes (TGFs), which are microsecond‐lasting enhanced gamma ray bursts with energy reaching tens of MeV related with lightning discharges (Briggs et al., 2010; Smith et al., 2005; Tavani et al., 2011). A wide variaty of observations of other High Energy Atmospheric Phenomena (HEAP) (Babich, 2003) demonstrate interactions between the thundercloud electric field and high‐energy particles; including gamma ray glow (also called Thunderstorm Ground Enhancement, TGE and long bursts; Chilingarian, 2013; Wada et al., 2021), neutron bursts (Babich, 2019; Babich et al., 2007; Chilingarian, Bostanjyan, Karapetyan, & Vanyan, 2012; Chilingarian, Bostanjyan, & Vanyan, 2012; Martin & Alves, 2010; Shah et al., 1985; Shyam & Kaushik, 1999;) and TGFs afterglow (Diniz et al., 2018, 2021; Enoto et al., 2017; Rutjes & Ebert, 2017).…”