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Title: Observed correlation between pulsating aurora and chorus waves at Syowa Station in Antarctica: A case study
Authors: Ozaki, Mitsunori
Yagitani, Satoshi
Ishizaka, Kazumasa
Shiokawa, Kazuo
Miyoshi, Yoshizumi
Kadokura, Akira
Yamagishi, Hisao
Kataoka, Ryuho
Ieda, Akimasa
Ebihara, Yusuke  kyouindb  KAKEN_id  orcid (unconfirmed)
Sato, Natsuo
Nagano, Isamu
Keywords: Syowa Station
ground-based observation
lower-band chorus
pulsating aurora
wave-particle interaction
Issue Date: Aug-2012
Publisher: American Geophysical Union
Journal title: Journal of Geophysical Research: Space Physics
Volume: 117
Issue: A8
Thesis number: A08211
Abstract: A high correlation between a pulsating auroral patch and grouped chorus waves was observed on 17 April 2006 at Syowa Station in Antarctica. The spatial distribution of aurora–chorus correlation coefficients is evaluated in order to determine the source region. A pulsating patch at the highest-correlation pixel shows a one-to-one correspondence with the intensity variation of the grouped chorus waves, consisting of successive rising-tone elements with a duration and spacing of 2–3 s and 20–30 s, respectively. The generation region of the chorus waves is estimated from the latitude and longitude dependence of the equatorial electron gyrofrequencies using the IGRF geomagnetic field model. The extent of the estimated latitude and longitude is consistent with the spatial distribution of the high-correlation aurora–chorus region. The time difference between the chorus waves and the scattered electrons is also evaluated to discuss the validity of the source region. It shows that electrons reached the ionosphere sooner than the associated chorus waves by ∼1 s, consistent with the theoretical value for conjugate pulsating aurora generated at the equator. These results support the hypothesis that pulsating aurora is caused by pitch angle scattering of high-energy electrons by whistler mode chorus waves, via a cyclotron resonance at the equator. These results are the first ground-based observations of high correlations between a spatially extended aurora and chorus waves.
Rights: ©2012. American Geophysical Union.
DOI(Published Version): 10.1029/2011ja017478
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