@article{oai:repo.qst.go.jp:00075699,
 author = {U. Abbasi, R. and T., Abu‐Zayyad and Allen, M. and Barcikowski, E. and W. Belz, J. and R. Bergman, D. and A. Blake, S. and Byrne, M. and Cady, R. and B.G.Cheon and Chiba, J. and Chikawa, M. and Fujii, T. and Fukushima, M. and Furlich, G. and Goto, T. and Hanlon, W. and Hayashi, Y. and Hayashida, N. and Hibino, K. and Honda, K. and Ikeda, D. and Inoue, N. and Ishii, T. and Ito, H. and Ivanov, D. and Jeong, S. and C. H. Jui, C. and Kadota, K. and Kakimoto, F. and Kalashev, O. and Kasahara, K. and Kawai, H. and Kawakami, S. and Kawata, K. and Kido, E. and B. Kim, H. and H. Kim, J. and H. Kim, J. and S. Kishigami, S. and R. Krehbiel, P. and Kuzmin, V. and J. Kwon, Y. and Lan, J. and LeVon, R. and P. Lundquist, J. and Machida, K. and Martens, K. and Matuyama, T. and N. Matthews, J. and Minamino, M. and Mukai, K. and Myers, I. and Nagataki, S. and Nakamura, R. and Nakamura, T. and Nonaka, T. and Ogio, S. and Ohnishi, M. and Ohoka, H. and Oki, K. and Okuda, T. and Ono, M. and Onogi, R. and Oshima, A. and Ozawa, S. and H. Park, I. and S. Pshirkov, M. and Remington, J. and Rison, W. and Rodeheffer, D. and C. Rodriguez, D. and Rubtsov, G. and Ryu, D. and Sagawa, H. and Saito, K. and Sakaki, N. and Sakurai, N. and Seki, T. and Sekino, K. and Shah, P.D. and Shibata, F. and Shibata, T. and Shimodaira, H. and K. Shin, B. and S. Shin, H. and D. Smith, J. and Sokolsky, P. and W. Springer, R. and T. Stokes, B. and A. Stroman, T. and Takai, H. and Takeda, M. and Takeishi, R. and Taketa, A. and Takita, M. and Tameda, Y. and Tanaka, H. and Tanaka, K. and Tanaka, M. and J. Thomas, R. and B. Thomas, S. and B. Thomson, G. and Tinyakov, P. and Tkachev, I. and Tokuno, H. and Tomida, T. and Troitsky, S. and Tsunesada, Y. and Uchihori, Y. and Udo, S. and Urban, F. and Vasiloff, G. and Wong, T. and Yamamoto, M. and Yamane, R. and Yamaoka, H. and Yamazaki, K. and Yang, J. and Yashiro, K. and Yoneda, Y. and Yoshida, S. and Yoshii, H. and Zundel, Z. and Uchihori, Yukio},
 issue = {13},
 journal = {Journal of Geophysical Research: Atmospheres},
 month = {May},
 note = {Bursts of gamma ray showers have been observed in coincidence with downward propagating negative leaders in lightning flashes by the Telescope Array Surface Detector (TASD). The TASD is a 700‐km2 cosmic ray observatory located in southwestern Utah, USA. In data collected between 2014 and 2016, correlated observations showing the structure and temporal development of three shower‐producing flashes were obtained with a 3‐D lightning mapping array, and electric field change measurements were obtained for an additional seven flashes, in both cases colocated with the TASD. National Lightning Detection Network information was also used throughout. The showers arrived in a sequence of 2–5 short‐duration (≤10 μs) bursts over time intervals of several hundred microseconds and originated at an altitude of ≃3–5 km above ground level during the first 1–2 ms of downward negative leader breakdown at the beginning of cloud‐to‐ground lightning flashes. The shower footprints, associated waveforms and the effect of atmospheric propagation indicate that the showers consist primarily of downward‐beamed gamma radiation. This has been supported by GEANT simulation studies, which indicate primary source fluxes of ≃1012–1014 photons for 16° half‐angle beams. We conclude that the showers are terrestrial gamma ray flashes, similar to those observed by satellites, but that the ground‐based observations are more representative of the temporal source activity and are also more sensitive than satellite observations, which detect only the most powerful terrestrial gamma ray flashes.},
 pages = {6864--6879},
 title = {Gamma Ray Showers Observed at Ground Level in Coincidence With Downward Lightning Leaders},
 volume = {123},
 year = {2018}
}