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Detection of transient ELF emission caused by the extremely intense cosmic gamma‐ray flare of 27 December 2004
Author(s) -
Tanaka Y. T.,
Hayakawa M.,
Hobara Y.,
Nickolaenko A. P.,
Yamashita K.,
Sato M.,
Takahashi Y.,
Terasawa T.,
Takahashi T.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl047008
Subject(s) - flare , sprite (computer graphics) , physics , astrophysics , cosmic ray , gamma ray , lissajous curve , transient (computer programming) , cosmic cancer database , astronomy , optics , computer science , operating system , computer vision
We report on the first clear detection of transient Extremely‐Low‐Frequency (ELF) signal caused by an extremely intense cosmic gamma‐ray flare. On 2004 December 27, the brightest gamma‐ray flare ever recorded was observed by numerous satellites. A transient ELF emission observed at Moshiri and Onagawa in Japan exactly coincided with the peak time of the flare, and its wide pulse width of ∼40 ms disfavors the possibility of lightning origin. Furthermore, the two horizontal components of ELF magnetic field data recorded at Esrange in Sweden showed clear transient Schumann resonance waveforms. The source direction determined by the Lissajous method roughly corresponds to the subflare point. The chance probability that a sprite occurs within 30 ms of the peak flare time is ∼0.025%, which again clearly excludes the sprite origin. Thus, a bright cosmic gamma‐ray flare is a new source of transient ELF radio signals observed on the Earth, although the emission mechanism needs to be clarified in future.