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Low‐latitude ELF‐whistlers observed in Taiwan
Author(s) -
Wang YunChing,
Wang Kaiti,
Su HanTzong,
Hsu RueRon
Publication year - 2005
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 - 10.1029/2005gl022412
Subject(s) - whistler , daytime , latitude , low latitude , geology , geophysics , plasmasphere , geomagnetic latitude , lightning (connector) , ionosphere , middle latitudes , atmospheric sciences , meteorology , physics , magnetosphere , geodesy , magnetic field , earth's magnetic field , power (physics) , quantum mechanics
Detections of ELF whistler‐like events at a low latitude location are reported. Events with frequencies between 60 and 100 Hz were recorded by the ELF station at the Lulin Observatory in Taiwan from August 26, 2003 to July 13, 2004. The most distinguished feature for these events is the frequency descent in the frequency‐time spectrograms, resembling terrestrial whistlers. Other notable features include (a) a long event duration averaging up to two minutes, (b) a daytime diurnal maximum occurring around 10 am, (c) a dominant magnetic field polarization in the north‐south direction with strength of a few to tens of pT, and (d) no detection of vertical electric fields. Similar events were only reported twice for the past thirty years: one at an auroral latitude site in Alaska and the other at a mid‐latitude site in California. Possible source mechanisms including magnetosheath lion roars and lightning‐generated whistlers are discussed.