X‐ray bursts associated with leader steps in cloud‐to‐ground lightning

Dwyer, J. R.; Rassoul, H. K.; Al‐Dayeh, M.; Caraway, L.; Chrest, A.; Wright, Brian D.; Kozak, E.; Jerauld, J.; Uman, M. A.; Rakov, Vladimir A.; Jordan, D. M.; Rambo, K. J.

doi:10.1029/2004gl021782

Cited by 181 publications

(250 citation statements)

References 17 publications

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“…Moore et al [2001] found x-rays during negative stepped leader descent at Langmuir Laboratory. Dwyer et al [2005] found similar results in Florida. Dwyer et al [2004aDwyer et al [ , 2004b have also detected X-radiation is association with rocket-triggered lightning at Camp Blanding, Florida.…”

Section: ]supporting

confidence: 62%

“…These details are obviously important in understanding apparent discrepancies between findings by Schonland, Viljoen and Halliday, and the more recent results beneath thunderclouds [Moore et al, 2001;Dwyer et al, 2004aDwyer et al, , 2004bDwyer et al, , 2005.…”

Section: ]mentioning

confidence: 93%

“…[53] Today, with the recent evidence (see Appendix B, note 20) that lightning can produce X-radiation at relatively close range [Moore et al, 2001;Dwyer et al, 2005], and can launch g radiation into space [Smith et al, 2005;Stanley et al, 2006;Williams et al, 2006], the coincidence results noted by Schonland and Viljoen [1933] seem plausible, but the long range paths for b rays outside the cloud where the electric field magnitude is often modest (tens of kV/m or less), are probably unrealistic. Nevertheless, Wilson's scenario for annihilating the (b ray-retarding) cloud top field by a lightning flash, to enable sustained propagation away from the cloud, may have an interesting parallel accounting for g radiation observed by the RHESSI satellite in space.…”

Section: ]mentioning

confidence: 99%

“…[66] It is ironic that the location in the immediate thunderstorm environment, below cloud base where energetic particles are best documented today [Moore et al, 2001;Dwyer et al, 2004aDwyer et al, , 2004bDwyer et al, , 2005 is not the location emphasized for prevalence by Wilson's [1956] final reflection on the problem. The essentially negative results of Schonland [1930] in his initial search beneath the cloud undoubtedly played a role here.…”

Section: Phase 5: Field Work-a Theory For the Thunderstormmentioning

confidence: 99%

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Origin and context of C. T. R. Wilson's ideas on electron runaway in thunderclouds

Williams

2010

J. Geophys. Res.

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[1] The publications, research notebooks and personal correspondence of C.T.R. Wilson are reviewed to understand his thinking on the idea of electron runaway in thunderclouds. The expansion cloud chamber, developed and refined over a period of nearly fifty years, is centrally important. Wilson's habit of research is characterized by a pattern of alternating between laboratory work with the cloud chamber and field observations of thunderclouds and the global electrical circuit. The evidence that the ionization tracks of electrons in the cloud chamber straightened with increasing energy was key to the idea of electron runaway, published in 1925. Despite numerous negative results by Wilson's colleagues Schonland, Halliday and others in searching for energetic particles in the vicinity of thunderclouds, Wilson supported the idea from its inception to his final publication in 1956. Wilson's notebooks indicate a conceptual awareness of runaway breakdown in thunderclouds 60 years in advance of contemporary theoretical publications. Definitive observational results on runaway breakdown in contemporary research were likely delayed for 60 years as a result of the unfortunate negative experimental results with inadequate equipment.

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Section: ]supporting

confidence: 62%

Section: ]mentioning

confidence: 93%

Section: ]mentioning

confidence: 99%

Section: Phase 5: Field Work-a Theory For the Thunderstormmentioning

confidence: 99%

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Origin and context of C. T. R. Wilson's ideas on electron runaway in thunderclouds

Williams

2010

J. Geophys. Res.

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“…Fig. 6(b) shows that the last two current pulses coincide with pronounced changes in the electric field at station 1, which are due to leader steps [25], [26].…”

Section: Currents Induced In the Vertical Conductor During Naturalmentioning

confidence: 96%

Experimental Study of Lightning-Induced Currents in a Buried Loop Conductor and a Grounded Vertical Conductor

Schoene

Uman

Rakov

et al. 2008

IEEE Trans. Electromagn. Compat.

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The angular distribution of energetic electron and X‐ray emissions from triggered lightning leaders

et al. 2013

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[1] We investigate individual X-ray bursts from lightning leaders to determine if energetic electrons at the source (and hence X-rays) are emitted isotropically or with some degree of anisotropy. This study was motivated by the work of Saleh et al. (2009), which found the falloff of X-rays in concentric radial annuli, covering all azimuthal directions in each annulus, from the lightning channel to be most consistent with an isotropic electron source. Here we perform a statistical analysis of angular and spatial distributions of X-rays measured by up to 21 NaI/PMT detectors at the International Center for Lightning Research and Testing site for 21 leader X-ray bursts from five leaders (including four dart-stepped leaders and one dart leader). Two procedures were used to complete this analysis. Procedure 1 found the first-order anisotropy, and procedure 2 tested whether or not the angular distribution was consistent with an isotropic distribution. Because higher-order anisotropies could be present in the data, a distribution that is not isotropic does not necessarily have a significant first-order anisotropy. Using these procedures, we find that at least 11 out of 21 X-ray bursts have a statistically significant first-order anisotropy, and hence those 11 are inconsistent with an isotropic emission. The remaining 10 bursts do not have significant first-order anisotropy. However, of those 10 bursts, 9 are inconsistent with isotropic emission, since they exhibit significant higher-order anisotropies. Since Saleh et al. (2009) did not consider anisotropies in the azimuthal direction, these new measurements of anisotropy do not necessarily contradict that work. Indeed, our analysis supports the finding that the X-ray emissions from lightning are inconsistent with a vertically downward beam. The level of anisotropy of the runaway electrons is important because it provides, in principle, information on the streamer zone in front of the leader and the electric field near the lightning leader tip.

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X‐ray bursts associated with leader steps in cloud‐to‐ground lightning

Cited by 181 publications

References 17 publications

Origin and context of C. T. R. Wilson's ideas on electron runaway in thunderclouds

Origin and context of C. T. R. Wilson's ideas on electron runaway in thunderclouds

Experimental Study of Lightning-Induced Currents in a Buried Loop Conductor and a Grounded Vertical Conductor

The angular distribution of energetic electron and X‐ray emissions from triggered lightning leaders

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