Circulation of Radon Progeny in the Terrestrial Atmosphere During Thunderstorms

Abstract

The terrestrial atmosphere is host to various sources of electric currents and gamma radiation ranging from the fair-weather current of picoamperes to hundreds of kiloampere lightning currents. Particle fluxes range from the single particles of the ambient population of secondary cosmic rays to huge particle showers from interactions of primary high-energy proton or nuclei with terrestrial atmosphere and electron-gamma ray avalanches from the electron accelerator operated in the thundercloud. Gamma radiation from the primordial radionuclides have the half-life comparable with the age of the Earth, and they contribute significantly to natural gamma radiation (NGR) at considerably low energies (<3 MeV). Radionuclides derived from the Earth crust can influence the electrical properties of the atmosphere and can influence human illness and death rates, result in DNA alterations, and chromosomal aberrations and weakening of immunity (Hunting et al., 2020). The static electric field in the lower atmosphere is modulated by the mobile particles carrying electrical charges, i.e., different types of hydrometeors, aerosols, small ions, and progeny of radioactive isotopes. The charge separation initiated by the updraft of moisture generates an electric field between differently charged layers emerging in the thundercloud; potential drop (voltage) in the cloud can reach hundreds of megavolts. Emerging near-surface electric field lifts charged aerosols with attached 222 Rn isotope and its progeny to the atmosphere. Correspondingly, the concentration of 222 Rn at surface decreases 10 times (Roffman, 1972; Wilkcning et al., 1966); the small ions and aerosols with attached 222 Rn are lifted up in seconds to tens of meters due to their large mobility. These gamma emitters significantly enhance low-energy natural gamma radiation measured by spectrometers located several meters above the ground (Chilingarian, 2018; Chilingarian et al., 2019a, 2019b). The rain returns long-lived progeny to the Earth recovering and somewhat

Transient Luminous Events in the Lower Part of the Atmosphere Originated in the Peripheral Regions of a Thunderstorm

“…Large sizes (12 × 12 × 24 cm) and low energy thresholds allow measurements of the energy spectra from 0.3 MeV up to 60 MeV. At the lower energies (less than 2 MeV) we can observe the contribution of the gamma radiation of 220 Radon progenies lifted to the atmosphere by NSEF [39]. The energy spectra above 3 MeV are due to TGE particles from the RREA avalanche reaching earth's surface.…”

Structure of thunderstorm ground enhancements

“…Correspondingly the fitted spectra depend on 5 parameters, analogically as to the primary cosmic ray spectrum measured by MAKET ANI surface array [8]: JTGE = A*E -𝛾 (1 + (E/Eknee) E ) Δ𝛾/𝟄 , where 𝞬 varies from 0.98 to 1.06, Δ𝞬 -from 2.46 to 3.17, and the sharpness of the knee 𝞊 from 2.34 to 2.66. Parameters of intense energy spectra measured on 22 September are summarized in Table 1 Spectra have a rather complicated shape before 10 MeV due to Radon progeny gamma radiation [9], ambiguities in detector response function calculation at low energies, and, possibly some unknown modulation effects in the atmospheric electric field. However, the differential energy spectra in the energy region10 -50 MeV follow the exponential law with very high accuracy.…”

Multi-messenger observations of thunderstorm-related bursts of cosmic rays

“…As we see from the figure, the enhancement of the gamma ray flux (selected by 001 coincidence) started at 17:45 long before the TGE maximum at 18:33. The disturbances of the NSEF just started and cannot initiate TGE, however, the 226 Radon progeny, which are attached to charged aerosols are lifted by the NSEF and cause enhancement of the count rate of the lower STAND1 detector's scintillator [35].…”