Open AccessObserved correlation between pulsating aurora and chorus waves at Syowa Station in Antarctica: A case study
Author(s) -
Ozaki Mitsunori,
Yagitani Satoshi,
Ishizaka Kazumasa,
Shiokawa Kazuo,
Miyoshi Yoshizumi,
Kadokura Akira,
Yamagishi Hisao,
Kataoka Ryuho,
Ieda Akimasa,
Ebihara Yusuke,
Sato Natsuo,
Nagano Isamu
Publication year - 2012
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011ja017478
Subject(s) - chorus , equator , physics , longitude , geophysics , ionosphere , electron precipitation , pitch angle , geology , latitude , atmospheric sciences , computational physics , magnetosphere , astronomy , magnetic field , art , literature , quantum mechanics
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.