Numerical analysis of 2010 high‐mountain (Tien‐Shan) experiment on observations of thunderstorm‐related low‐energy neutron emissions

Abstract

[1] The high-mountain experiment in a thunderstorm atmosphere, in which "extraordinary high flux of low-energy neutrons" was detected, is analyzed. Due to the lack of data on the radiation source, we do not analyze directly measured absolute count rates. Instead, we address the experimental configuration, namely, simultaneous measurements by shielded and unshielded helium counters, which allow a comparison of relative count rates and, thus, verifying the species of the detected radiation. Results of Monte Carlo simulations of neutron transport executed without aprioristic assumptions, using only data on the experimental configuration, have raised strong doubts as to whether the detected increases of the count rates can be attributed to neutrons. Results of simulations allowing for the neutron transport in atmosphere from distant (100-500 m) photoneutron source with spectrum in the range 0-20.1 MeV produced by relativistic runaway electron avalanche bremsstrahlung demonstrate that ratios R of the count rates of shielded and unshielded counters below 1 keV are manyfold higher than the ratios R exp ≈ 0.34-1.06 of the measured count rates. In the total range 0-20.1 MeV, the R magnitudes vary from 0.14 to 0.84 depending on the distance to the neutron source. Results of simulations of γ rays transport executed without aprioristic assumptions demonstrate that, most likely, hard γ rays with energies ε γ > 1 MeV were detected. We note that in thunderstorm environment, a selection is required of neutrons and γ rays, for which the time-of-flight technique is the most adequate.Citation: Babich, L. P., E. Bochkov, J. R. Dwyer, I. M. Kutsyk, and A. N. Zalyalov (2013), Numerical analysis of 2010 high-mountain (Tien-Shan) experiment on observations of thunderstorm-related low-energy neutron emissions,

Correlations Between Secondary Cosmic Ray Rates and Strong Electric Fields at Lomnický štít

“…There may be short spikes inside the 2 min averaged count rate increases. Also, other authors indicate relations between atmospheric discharge and short time increases of neutrons (including thermal ones) at the same site (e.g., Babich et al, 2013;Kozlov et al, 2013;Martin & Alves, 2010;Starodubtsev et al, 2012;Tsuchiya et al, 2012). Recording time of each pulse, as well as anticoincidence between different channels of SEVAN, now in progress, may help in clarification.…”

Radiocarbon Production by Thunderstorms

“…In view of the shortcomings in Babich and Roussel‐Dupré () and given new experimental (Briggs et al, ; Chilingarian et al, , , , , ; Connaughton et al, ; Cummer et al, , ; Gurevich et al, ; Ishtiaq et al, ; Kelley et al, ; Kuroda et al, ; Marisaldi, Fuschino et al, ; Marisaldi, Tavani et al, ; Martin & Alves, ; Starodubtsev et al, ; Tavani et al, ; Tsuchiya et al, , , , ) and computational (Babich, ; Babich et al, , ; Babich, Bochkov, Kutsyk et al, ; Babich, Bochkov, Donskoĭ et al, ; Babich, Bochkov, Kutsyk et al, ; Babich, Bochkov, Dwyer et al, ; Babich et al, ; Carlson et al, ; Celestin, Xu, & Pasko, ; Dwyer, ; Dwyer, Grefenstette, & Smith, ; Kelley et al, ; Tsuchiya et al, ; Xu, Celestin, & Pasko, ) data on thunderstorm γ rays and neutrons, reanalyzing of the problem of the production by thunderstorms is expedient. The new analysis is based not on a limited number of detections of thunderstorm neutrons as in Babich and Roussel‐Dupré () but on a vast amount of new data obtained from detecting of thunderstorm ground enhancements, i.e., enhanced fluxes of high‐energy electrons, hard γ rays, and neutrons on the Earth's surface, which have been copiously collected on Mount Aragats, Armenia (3250 m above sea level) (Chilingarian et al, , , , , ) and at other sites worldwide: Japan (sea level and 2770 m above sea level) (Tsuchiya et al, , , ); Tibet, China (4300 m above sea level) (Tsuchiya et al, ); Himalayas, India (2743 m above sea level) (Ishtiaq et al, ; Shah et al, ); and Tien Shan, Kazakhstan (3340 m above sea level) (Gurevich et al,…”

“…It is pertinent to note that, as ranges of photons with energies ε γ ≥ ε th,N greatly exceed transverse sizes of lightning channels, the neutron‐producing reactions occur outside the channels (Babich, ; Babich, Bochkov, Kutsyk et al, ; Babich, Bochkov, Dwyer et al, ; Babich et al, ). The neutron pulses may only correlate with lightning EMPs; rather frequently, they occur in advance of them or even do not correlate with them.…”

“…Babich and Roussel-Dupré (2007) concluded that thunderstorm neutrons nowadays deposit weakly into the 14 6 C concentration on average across the globe, but locally, especially in tropics, the 14 6 C production by thunderstorms, possibly, compete with that by cosmic irradiation. In view of the shortcomings in Babich and Roussel-Dupré (2007) and given new experimental (Briggs et al, 2010;Chilingarian et al, 2010Chilingarian et al, , 2012Chilingarian et al, , 2013Chilingarian et al, , 2016Chilingarian et al, , 2017Connaughton et al, 2011;Cummer et al, 2005Cummer et al, , 2011Gurevich et al, 2012;Ishtiaq et al, 2016;Kelley et al, 2015;Kuroda et al, 2016;Marisaldi, Fuschino et al, 2010;Martin & Alves, 2010;Starodubtsev et al, 2012;Tavani et al, 2011;Tsuchiya et al, 2007Tsuchiya et al, , 2009Tsuchiya et al, , 2011Tsuchiya et al, , 2012 and computational (Babich, 2014;Babich et al, , 2008Babich, Bochkov, Donskoĭ et al, 2010;Babich, Bochkov, Dwyer et al, 2013;Babich et al, 2014;Carlson et al, 2010;Dwyer, 2008;Dwyer, Grefenstette, & Smith, 2008;Kelley et al, 2015;Tsuchiya et al, 2012; data on thunderstorm γ rays and neutrons, reanalyzing of the problem of the 14 6 C production by thunderstorms is expedient. The new analysis is based not on a limited number of detections of thunderstorm neutrons as in Babich and Roussel-Dupré (2007) but on a vast amount of new data obtained from detecting of thunderstorm ground enhancements, i.e., enhanced fluxes of high-energy electrons, hard γ rays, and neutrons on the Earth's surface, which ha...…”

Production mechanisms of leptons, photons, and hadrons and their possible feedback close to lightning leaders

“…Further measurements were performed [ Shyam and Kaushik , ; Bratolyubova‐Tsulukidze , ; Tsuchiya et al , ; Kozlov et al , , and references therein] enhancing the present knowledge about these phenomena. However, Babich et al [, , ] have shown that the counters in these experiments have been sensitive also to other ionizing emissions. More reliable observations were performed by Chilingarian et al [, ].…”