Time‐Resolved Leader Spectra of Downward Terrestrial Gamma‐Ray Flashes Observed at the Telescope Array Surface Detector

Abstract The first time‐resolved leader spectra associated with a downward Terrestrial Gamma‐ray Flash (TGF) observed by the Telescope Array Surface Detector (TASD) were recently reported by Kieu et al. (2024, https://doi.org/10.1029/2024JD041720 ). Building on that study, this paper presents the time‐resolved leader spectra of two additional downward TGFs detected by the TASDs. The first TGF, triggered once, occurred during the Initial Breakdown Pulses (IBPs) of a negative return stroke with a low peak current (18.5 kA). The second TGF, triggered twice, was detected during the initial leader stage of a high‐peak‐current (133.4 kA) return stroke. The electric field change (E‐change) waveform caused by the leader preceding this return stroke had a brief duration (1.2 ms) and lacked strong IBPs. These unusual characteristics suggest that this lightning flash may represent a distinct type of event associated with TGF detection not previously observed at the TASD. Most importantly, the optical emissions of both TGF events align with previous findings and show ion emission lines before and after TGF detections while only neutral emission lines were recorded at the moment of TGF detections.

Authors

R. Sakamoto (ORCID: https://orcid.org/0000-0002-4453-953X)
Marcelo M. F. Saba (ORCID: https://orcid.org/0000-0001-5857-761X)
T. Sako (ORCID: https://orcid.org/0000-0002-2589-8561)
N. Kieu (ORCID: https://orcid.org/0000-0002-5811-3513)
K. Smout
J. Mazich
P. Tinyakov (ORCID: https://orcid.org/0000-0002-0649-6444)
O. Kalashev (ORCID: https://orcid.org/0000-0002-7982-1842)
Michal Vrábel (ORCID: https://orcid.org/0000-0003-3219-3874)
Shigehiro Nagataki (ORCID: https://orcid.org/0000-0002-7025-284X)
I. Komae
H. Shimodaira
N. Hayashida
Takaaki Ishii (ORCID: https://orcid.org/0000-0001-6690-7834)
H.S. Shin (ORCID: https://orcid.org/0009-0001-6701-2431)
W. Hanlon (ORCID: https://orcid.org/0000-0002-0109-4737)
S. Jeong (ORCID: https://orcid.org/0000-0002-2674-6172)
Y.-J. Kwon (ORCID: https://orcid.org/0000-0001-9448-5691)
Shinji Sato (ORCID: https://orcid.org/0000-0002-7888-2117)
S. B. Thomas (ORCID: https://orcid.org/0000-0002-8828-7856)
Masao Murakami (ORCID: https://orcid.org/0000-0001-9530-0337)
John Belz (ORCID: https://orcid.org/0000-0001-9779-2750)
J. H. Kim
Z. Gerber
M. Kuznetsov (ORCID: https://orcid.org/0000-0001-6281-9503)
P. Sokolsky (ORCID: https://orcid.org/0000-0003-3391-1022)
T. M. Knight (ORCID: https://orcid.org/0000-0003-2486-7672)
K. Takahashi
K. Kasahara (ORCID: https://orcid.org/0000-0001-5611-3301)
Diego Rhamon Reis da Silva (ORCID: https://orcid.org/0000-0002-8714-1046)
G. B. Thomson
P. R. Krehbiel (ORCID: https://orcid.org/0000-0003-2963-1837)
Noémie Globus (ORCID: https://orcid.org/0000-0001-9011-0737)
G. Furlich (ORCID: https://orcid.org/0000-0002-8723-7646)
K. Hibino (ORCID: https://orcid.org/0000-0001-9259-6371)
Hiroyuki Sagawa
М. С. Пширков (ORCID: https://orcid.org/0000-0002-5746-2017)
Atsushi Matsuzawa (ORCID: https://orcid.org/0000-0001-8303-3905)
Ryuji Takeishi (ORCID: https://orcid.org/0000-0001-6335-5317)
N. Sakurai (ORCID: https://orcid.org/0000-0002-1002-217X)
M. J. Lee (ORCID: https://orcid.org/0000-0003-4528-4601)
W. Rison (ORCID: https://orcid.org/0000-0003-1822-2851)
K. H. Lee
D. Ikeda (ORCID: https://orcid.org/0000-0003-1382-9267)
K. Y. Park
C. C. H. Jui (ORCID: https://orcid.org/0000-0002-1902-3478)
Christian N. Koyama (ORCID: https://orcid.org/0000-0003-3469-9764)
A. Taketa (ORCID: https://orcid.org/0000-0001-6936-4118)
T. Abu‐Zayyad (ORCID: https://orcid.org/0000-0001-5206-4223)
B. K. Shin
F. Urban (ORCID: https://orcid.org/0000-0001-9403-767X)
Donald C. Warren (ORCID: https://orcid.org/0000-0002-3222-9059)
Dario Mazzucco
Tom A. Warner (ORCID: https://orcid.org/0000-0001-8589-3351)
Г. И. Рубцов (ORCID: https://orcid.org/0000-0002-6106-2673)
K. Yamazaki (ORCID: https://orcid.org/0000-0002-3771-2496)
Hao-Ning He (ORCID: https://orcid.org/0000-0002-8941-9603)
A. Petrizze
Y. Zhezher (ORCID: https://orcid.org/0000-0002-3588-9706)
Tatsuo Nakayama
Ivan Toucedo Cruz (ORCID: https://orcid.org/0000-0003-3185-4597)
D. Rodeheffer (ORCID: https://orcid.org/0000-0003-3785-1311)
E. Kido (ORCID: https://orcid.org/0000-0001-7278-3049)
J. Shikita
H. Oshima (ORCID: https://orcid.org/0000-0002-3346-2522)
Koji Mizuno (ORCID: https://orcid.org/0000-0002-5297-1365)
C. Rott (ORCID: https://orcid.org/0000-0002-6958-6033)
I. Buckland
Monica Allen (ORCID: https://orcid.org/0000-0003-4440-6451)
Yoshio Kawachi (ORCID: https://orcid.org/0009-0006-1961-651X)
Kunimoto Komatsu (ORCID: https://orcid.org/0000-0002-9414-5336)
Shunsuke Sakurai (ORCID: https://orcid.org/0000-0002-0465-3274)
K. Kadota (ORCID: https://orcid.org/0000-0001-7672-1945)
M. Przybylak (ORCID: https://orcid.org/0009-0004-6246-6620)
I. Tkachev (ORCID: https://orcid.org/0000-0003-1681-8408)
T. Nonaka (ORCID: https://orcid.org/0000-0003-4795-500X)
R. LeVon
K. Kawata (ORCID: https://orcid.org/0000-0001-6332-2005)
Jon Paul Lundquist (ORCID: https://orcid.org/0000-0002-4245-5092)
F. Kakimoto
I. A. Vaiman
Megumi Kuroiwa (ORCID: https://orcid.org/0000-0002-4075-4881)
Y. Tameda (ORCID: https://orcid.org/0000-0001-9750-5440)
K. Fujita (ORCID: https://orcid.org/0009-0006-8756-3333)
T. A. Stroman
S. Ozawa
M. Takeda
Rasha Abbasi (ORCID: https://orcid.org/0000-0001-6141-4205)
Dongsu Ryu (ORCID: https://orcid.org/0000-0002-5455-2957)
Kazuhiko Endo (ORCID: https://orcid.org/0000-0002-3517-3580)
Jackson Remington (ORCID: https://orcid.org/0000-0003-2952-4919)
John A. Mathews (ORCID: https://orcid.org/0000-0002-4380-7563)
J. N. Matthews
M. Onishi
D. R. Bergman
M. Fukushima (ORCID: https://orcid.org/0009-0004-1070-2724)
K. Komori (ORCID: https://orcid.org/0000-0002-4092-9602)
M. A. Stanley (ORCID: https://orcid.org/0000-0002-9204-4742)
Н. Сакаки (ORCID: https://orcid.org/0000-0003-3745-8958)
Daiki Sato (ORCID: https://orcid.org/0000-0001-8528-2315)
M. Tanaka (ORCID: https://orcid.org/0000-0002-4697-894X)
A. Fedynitch
K. Nakagawa
Z. Zundel (ORCID: https://orcid.org/0000-0002-2456-0606)
Francisco J. Gordillo‐Vázquez (ORCID: https://orcid.org/0000-0002-0719-8203)
S. Troitsky (ORCID: https://orcid.org/0000-0001-6917-6600)
Y. Takagi
I. Kharuk
B. T. Stokes
Y. Kusumori
M. Kudenko
J. Zvirzdin (ORCID: https://orcid.org/0009-0005-5418-0654)
R. Kobo
Jihyun Kim (ORCID: https://orcid.org/0000-0002-8814-031X)
M. Potts (ORCID: https://orcid.org/0000-0002-1255-4735)
H. Tachibana (ORCID: https://orcid.org/0000-0003-1028-3959)
Ryo Higuchi (ORCID: https://orcid.org/0009-0008-1058-216X)
William Campbell (ORCID: https://orcid.org/0009-0000-9428-3133)
M. Mori (ORCID: https://orcid.org/0000-0003-1368-6593)
T. Shibata
Y. Tsunesada (ORCID: https://orcid.org/0000-0001-9238-6817)
T. Fujii
J. D. Smith (ORCID: https://orcid.org/0000-0002-3607-8390)
M. Takita (ORCID: https://orcid.org/0000-0003-0435-5362)
N. Okazaki
T. Nakamura
Y. Nakayama
T. Tomida
S. Udo
B. G. Cheon
M. Nakahara
S. Ogio
I. H. Park
K. Shinozaki
H. Ohoka
K. Fujisue
A. Oshima
S. W. Kim
H. Matsushita
Б. Лубсандоржиев
K. Sekino
K. Tanaka (ORCID: https://orcid.org/0009-0000-0890-2859)
D. Ivanov (ORCID: https://orcid.org/0000-0002-9270-5926)

Institutions

Université Libre de Bruxelles (BE)
Shinshu University (JP)
High Energy Accelerator Research Organization (JP)
Shibaura Institute of Technology (JP)
Chubu University (JP)
Tokyo City University (JP)
Osaka Electro-Communication University (JP)
University of Nova Gorica (SI)
Loyola University Chicago (US)
Yonsei University (KR)
Lomonosov Moscow State University (RU)
Brookhaven National Laboratory (US)
Czech Academy of Sciences (CZ)
New Mexico Institute of Mining and Technology (US)
University of Utah (US)
Purple Mountain Observatory (CN)
Osaka City University (JP)
University of Łódź (PL)
Kanagawa University (JP)
Kavli Institute for Particle Astrophysics and Cosmology (US)
National Centre for Nuclear Research (PL)
Institute for Nuclear Research (RU)
Institute of Physics, Academia Sinica (TW)
Astrobiology Center (JP)
Association for the Development of Earthquake Prediction (JP)
FZU ‒ Institute of Physics of the Academy of Sciences of the Czech Republic (CZ)
Korea Institute of Geoscience and Mineral Resources (KR)
Instituto de Astrofísica de Andalucía (ES)
Osaka Metropolitan University (JP)
Institute of Particle and Nuclear Studies
Hanyang University (KR)
Ulsan National Institute of Science and Technology (KR)
Hiroshima City University (JP)
University of Yamanashi (JP)
The University of Tokyo (JP)
Kōchi University (JP)
Instituto Nacional de Pesquisas Espaciais (BR)
Sungkyunkwan University (KR)
National Institute of Information and Communications Technology (JP)
Stanford University (US)

Publication Details

Journal: Journal of Geophysical Research Atmospheres
Published: 2025-08-16
DOI: https://doi.org/10.1029/2025jd043812
Citations: 1
Primary Topic: Lightning and Electromagnetic Phenomena
Type: article
Field-Weighted Citation Impact: 1.15

Funders

National Science Foundation
Fundação de Amparo à Pesquisa do Estado de São Paulo
Japan Society for the Promotion of Science

Time‐Resolved Leader Spectra of Downward Terrestrial Gamma‐Ray Flashes Observed at the Telescope Array Surface Detector

Authors

Institutions

Publication Details

Funders

Time‐Resolved Leader Spectra of Downward Terrestrial Gamma‐Ray Flashes Observed at the Telescope Array Surface Detector

Time‐Resolved Leader Spectra of Downward Terrestrial Gamma‐Ray Flashes Observed at the Telescope Array Surface Detector

Abstract

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