Location of Negative Charge Associated with Continuing Current of Upward Lightning Flash in Winter

Saito, Mikihisa; Ishii, Masaru; Kawamura, Hironao; Shindo, Takatoshi

doi:10.1541/ieejpes.129.929

Cited by 16 publications

(15 citation statements)

References 7 publications

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“…Monte Carlo simulations showed that the number of neutrons and the characteristic time scale of their decay were consistent with a TGF about as bright as those seen from space, with the same gamma ray spectrum, aimed downward at the ground from an altitude of 1.0 km above the tower. This altitude is consistent with the typical altitude of the main negative charge center in winter thunderstorms in this region (Saito et al, ). A similar TGF event at another site on the western Honshu coast was later seen by Enoto et al (), and a similar conclusion reached, with the additional and conclusive observation of the β + decay of the radioactive nuclei left behind by the neutron photoproduction.…”

Section: Observationssupporting

confidence: 90%

Characterizing Upward Lightning With and Without a Terrestrial Gamma Ray Flash

et al. 2018

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We compare two observations of gamma rays before, during, and after lightning flashes initiated by upward leaders from a tower during low-altitude winter thunderstorms on the western coast of Honshu, Japan. While the two leaders appear similar, one produced a terrestrial gamma ray flash (TGF) so bright that it paralyzed the gamma ray detectors while it was occurring and could be observed only via the weaker flux of neutrons created in its wake, while the other produced no detectable TGF gamma rays at all. The ratio between the indirectly derived gamma ray fluence for the TGF and the 95% confidence gamma ray upper limit for the gamma ray quiet flash is a factor of 1.0 × 10 7 . With the only two observations of this type providing such dramatically different results-a TGF probably as bright as those seen from space and a powerful upper limit-we recognize that weak, subluminous TGFs in this situation are probably not common, and we quantify this conclusion. While the gamma ray quiet flash appeared to have a faster leader and more powerful initial continuous current pulse than the flash that produced a TGF, the TGF-producing flash occurred during a weak gamma ray glow, while the gamma ray quiet flash did not, implying a higher electric field aloft when the TGF was produced. We suggest that the field in the high-field region approached by a leader may be more important for whether a TGF is produced than the characteristics of the leader itself. Plain Language SummaryBright flashes of high-energy radiation (gamma rays) have been seen along with some lightning, usually beamed upward into space. These terrestrial gamma ray flashes (TGFs) are so bright that someone caught in the middle of one could get a hazardous radiation dose, but that region is generally in the middle of a thundercloud where airplanes seldom go. Just a few TGFs have been seen beamed downward toward the ground. We looked at two very similar-but unusual-lightning flashes that went upward into the clouds from the top of a tower in Japan in the winter, when storms are very close to the ground. One produced an enormously bright downward TGF that paralyzed our detectors on the ground, while the other produced none at all. We find evidence that the TGF occurred because the electric field in the cloud may have been higher than it was during the lightning that did not produce radiation. We also point out that this pair of events adds to previous evidence that TGFs are an "all-or-nothing" sort of event rather than having a continuous range of brightness from weak to strong.

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Section: Observationssupporting

confidence: 90%

Characterizing Upward Lightning With and Without a Terrestrial Gamma Ray Flash

et al. 2018

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“…Even though the BOLT source altitude distributions are very different during winter and summer, the BOLT temperature distributions during both winter and summer peak near −10 °C. Because most of the BOLT source locations correspond to charge regions, our results using previous observations indicate that charge separation is active near the −10 °C level in both winter and summer thunderstorms, implying that a noninductive charging mechanism plays an important role in thunderstorm electrification in both winter and summer thunderstorms.…”

Section: Discussionmentioning

confidence: 99%

Three‐dimensional radio images of winter lightning in japan and characteristics of associated charge structure

Yoshida

Yoshikawa

Adachi

et al. 2018

IEEJ Transactions Elec Engng

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We conducted lightning observational campaigns using a three‐dimensional (3D) lightning mapper called the Broadband Observation network for Lightning and Thunderstorms (BOLT) and C‐band radar to further understand the distinct characteristics of winter lightning in the coastal area of the Sea of Japan. We succeeded in locating 3D intracloud (IC) flashes, cloud‐to‐ground (CG) flashes, and upward lightning during winter. The basic characteristics of winter lightning, such as leader speeds and charge structure associated with an IC discharge, are similar to summer lightning. A noticeable difference between the winter lightning and the summer lightning is that the altitudes of the source locations associated with winter lightning are substantially lower than those associated with summer lightning. We performed a statistical comparison of winter and summer lightning. This comparison shows that the BOLT source altitude distributions during winter and summer peak at 2.1 and 7.5 km, respectively. Conversely, the distributions of the BOLT temperatures, which are the temperatures corresponding to the BOLT source altitudes, during both winter and summer show similar trends and have large values near −10 °C. These results indicate that a similar charge separation process, likely a noninductive charging mechanism, primarily contributes to thunderstorm electrification during both winter and summer. We show that the horizontal extent of the winter flashes is substantially larger than that of the summer flashes. This result implies that the charge regions in winter thunderstorms cover a wide area and, therefore, produce CG flashes with large charge transfers. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

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“…Though in the winter lightning area in Japan, both positive charges in clouds which produced positive CG flashes in winter [11], and negative charges neutralized by lightning continuing currents in winter [12], were located at similar temperature heights around −10 °C.…”

Section: B Temperature In High Altitudementioning

confidence: 96%

Probability of lightning hits to tall structures taking account of upward lightning

Ishii

Saito

Fujii

et al. 2010

2010 Asia-Pacific International Symposium on Electromagnetic Compatibility

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It was revealed that serious lightning faults of high voltage power transmission lines in winter along the coastal area of the Sea of Japan were due to upward lightning initiated from transmission towers. Wind turbines in the same region, reportedly suffer from high lightning fault rate, must also generate frequent upward lightning. Taking account of the aerological data which indicate the heights of the charged region in thunderclouds, a method to evaluate frequency of upward lightning from tall structures in cold regions of Japan in winter is proposed. With this new method, it is possible to evaluate the probability of lightning hits to tall structures in Japan through the year.

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Location of Negative Charge Associated with Continuing Current of Upward Lightning Flash in Winter

Cited by 16 publications

References 7 publications

Characterizing Upward Lightning With and Without a Terrestrial Gamma Ray Flash

Characterizing Upward Lightning With and Without a Terrestrial Gamma Ray Flash

Three‐dimensional radio images of winter lightning in japan and characteristics of associated charge structure

Probability of lightning hits to tall structures taking account of upward lightning

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