Neutron generation in lightning bolts

Shah, G. N.; Razdan, H.; Bhat, C. L.; Ali, Q. M.

doi:10.1038/313773a0

Cited by 104 publications

(122 citation statements)

References 7 publications

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“…It was not until 1985 that a positive result was obtained. In an experiment lasting three years and conducted with a refined configuration in a high mountainous region (the Himalayas, altitude z = 2743 m), Shah et al [1985] were able to measure statistically significant neutron flux increases above background and correlated with lightning electromagnetic pulses (EMP). Later statistically significant increases in neutron fluxes were observed near sea level during thunderstorms [Shyam and Kaushik, 1999;Kuzhevskij, 2004;Gusev et al, 2009] and terrestrial neutron flashes were also detected aboard an artificial satellite of the Earth [BratolyubovaTsulukidze et al, 2004].…”

Section: Introductionmentioning

confidence: 99%

“…[4] Absorption of neutrons in dense lower layers of the atmosphere is so strong that the predicted values of neutron yield N n in stratospheric discharges, even in the field of large thundercloud charges, are insufficient to account for the increases in neutron fluxes observed on the Earth's surface [Shah et al, 1985;Shyam and Kaushik, 1999;Kuzhevskij, 2004;Gusev et al, 2009] by g emission in the stratosphere [Babich, 2006Babich and RousselDupré, 2007]. Assuming a source of g emission responsible for (g, n) reactions located in the stratosphere, large delay times of neutron arrival at the detector relative to the lightning EMP t del , detected by Shah et al [1985], can be explained, but it is impossible to account for t del ≤ 100 ms [Babich, 2006Babich and Roussel-Dupré, 2007].…”

Section: Introductionmentioning

confidence: 99%

“…Assuming a source of g emission responsible for (g, n) reactions located in the stratosphere, large delay times of neutron arrival at the detector relative to the lightning EMP t del , detected by Shah et al [1985], can be explained, but it is impossible to account for t del ≤ 100 ms [Babich, 2006Babich and Roussel-Dupré, 2007].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore to interpret the thunderstorm correlated neutron increases [Shah et al, 1985;Shyam and Kaushik, 1999;Kuzhevskij, 2004;Gusev et al, 2009] it is necessary to assume a tropospheric source of (g, n) reactions. This is the case because the hard g rays were observed to be associated with tropospheric sources [cf., e.g., Eack et al, 1996;Chubenko et al, 2000;Torii et al, 2002;Dwyer et al, 2004;Tsuchiya et al, 2007Tsuchiya et al, , 2009, and references therein].…”

Section: Introductionmentioning

confidence: 99%

“…[5] The (g, n) yield N n ≈ 4 · 10 13 neutrons estimated for lightning [Babich and Roussel-Dupré, 2007] is sufficient to account for the on-ground thunderstorm correlated neutron increases, especially at the high mountain observatory [Shah et al, 1985]. However, recently Tsuchiya et al communicated an observation of hard g ray burst at the altitude 2770 m (almost the same altitude as in the neutron observations by Shah et al), the source of which the authors, basing on measurements of electric field and optical emissions, connected with mountain top thunderclouds rather than with lightning [Tsuchiya et al, 2007[Tsuchiya et al, , 2009.…”

Section: Introductionmentioning

confidence: 99%

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Localization of the source of terrestrial neutron bursts detected in thunderstorm atmosphere

et al. 2010

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[1] To localize an altitude of the neutron source responsible for the neutron flux enhancements observed on the ground, numerical simulations of photonuclear production and transport to on-ground detector locations were carried out. The neutron fluence calculated for the volumetric source located at the altitudes 8-12 km is consistent with that estimated from neutron numbers measured on the ground. This altitude range is consistent with the idea that the burst of hard g rays detected recently by Tsuchiya et al. (2007Tsuchiya et al. ( , 2009 originate from a volumetric intracloud g ray source. Most likely, the photonuclear reactions caused by bremsstruhlung of descending relativistic runaway electron avalanches account for the neutron flux increases observed in the thunderstorm atmosphere.Citation: Babich, L. P., E. I. Bochkov, I. M. Kutsyk, and R. A. Roussel-Dupré (2010), Localization of the source of terrestrial neutron bursts detected in thunderstorm atmosphere,

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Localization of the source of terrestrial neutron bursts detected in thunderstorm atmosphere

et al. 2010

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

Babich¹,

Bochkov²,

Dwyer

et al. 2013

JGR Space Physics

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[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,

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Observation of 2.45 MeV neutrons correlated with natural atmospheric lightning discharges by Lead‐Free Gulmarg Neutron Monitor

et al. 2016

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The first experimental evidence of detecting the neutrons correlated with the natural atmospheric lightning discharges (NALD) was obtained with Lead‐Free Gulmarg Neutron Monitor (LFGNM) operating at High Altitude Research Laboratory, Gulmarg, Kashmir, India, and was reported in the year 1985. The neutron observations still continue with LFGNM. However, the current configuration of LFGNM is the upgraded version of the system used earlier to record neutron bursts (in the recording period of 320 μs in four successive electronic gates of 80 μs each) supposedly originating from an NALD. In the current system the neutron recording time period/interval has been extended to 1260 μs with 63 successive gates of 20 μs each. The system also simultaneously records the differential times—maximum up to 14—between the consecutive strokes of a multistroke lightning flash. The distance between an NALD channel and LFGNM setup is determined empirically by making use of the time delay (td)/time of flight (TOF) measurement of the first detected neutron subsequent to the sensing of the electrostatic field variation caused by the initiation of an NALD in the ambient atmosphere of the LFGNM setup. Assuming a priori incident energy as 2.45 MeV of the detected neutrons supposedly generated due to the fusion of deuterium ions in the lightning discharge channel leads to quantifying the neutron emission flux if the NALD channel distance with respect to the LFGNM setup is established. In this paper we discuss the experiment and the time profiles of several of a large number of the major neutron burst events recorded with LFGNM in association with NALDs. Moreover, a rare and an extraordinary neutron burst event, in terms of its associated “td/TOF” of first detected neutron after triggering, recorded by this system is specifically discussed. In this event, the recorded TOF of 14 μs of the escaping neutron detected by the system immediately after getting triggered by the NALD that struck a nearby tree found located just around 300 m (physically measured) away from the detector position indicates the energy of the detected neutron ϵn ≈2.45 MeV. In the light of this only event, we, therefore, cautiously suggest deuteron‐deuteron fusion reaction, 2H(2H,n)3He, as one of the possible mechanisms of the neutron generation correlated with an NALD. Nonetheless, the observations so far have reconfirmed production of neutrons in an NALD.

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Neutron generation in lightning bolts

Cited by 104 publications

References 7 publications

Localization of the source of terrestrial neutron bursts detected in thunderstorm atmosphere

Localization of the source of terrestrial neutron bursts detected in thunderstorm atmosphere

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

Observation of 2.45 MeV neutrons correlated with natural atmospheric lightning discharges by Lead‐Free Gulmarg Neutron Monitor

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