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IAGA 2005. Tracing Geomagnetic Conjugate Points by means of Extremely Similar Interhemispheric Auroras. N. Sato (1), A. Kadokura (1), Y. Ebihara (1) , H. Deguchi (1), and T. Saemundsson (2) National Institute of Polar Research, Tokyo, Japan (nsato@nipr.ac.jp)
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IAGA 2005 Tracing Geomagnetic Conjugate Points by means of Extremely Similar Interhemispheric Auroras N. Sato (1), A. Kadokura (1), Y. Ebihara (1) ,H. Deguchi (1), and T. Saemundsson (2) National Institute of Polar Research, Tokyo, Japan (nsato@nipr.ac.jp) Science Institute, University of Iceland, Iceland National Institute of Polar Research (NIPR)
Auroral Conjugate Observation at Syowa and Iceland Visualization of the conjugate foot prints of the geomagnetic field lines
Mapping of Northern/Southern hemispheres with geomagnetic coordinate
Conjugate point of Syowa Station (IGRF model) Comparison of geomagnetic parameters (Epoch: 23:20:00 UT, 26 Sep, 2003)
All-Sky Image and Geomagnetic meshat 120 km altitude SYOWA TJORNES Magnetic zenith at 23:23:00 UT on Sep. 26, 2003
Projection on Geomagnetic planeat 120 km altitude SYOWA TJORNES at 23:23:00 UT on Sep. 26, 2003 (elevation > 10゚)
Abstract of the Syowa-Iceland Auroral Conjugate Observation, so far • Starting from 1984 (20 years anniversary) • Executed every year in the equinox season, mainly in September, for about two weeks • Simultaneous darkness for about 4 hours • Only 2~3 nights of simultaneous observation in one season, mainly due to weather condition • Good conjugate event is rare ★September 26, 2003 event : The best conjugate event in the 20 year history
H D HAD HAD YOR YOR UPS UPS NUR NUR SAMNET data Pi2 onset : 23:18 UTOnset occurred at westward of Iceland meridian September 26, 2003 event
September 26, 2003 event all-sky TV data (23:19:30~23:23:50 UT, 10 sec interval) MN TJR W E S MS SYW W E N TJR SYW TJR SYW
September 26, 2003 event all-sky TV data (23:24:00~23:28:20 UT, 10 sec interval) TJR SYW TJR SYW TJR SYW
September 26, 2003 event all-sky TV data (23:28:30~23:32:50 UT, 10 sec interval) TJR SYW TJR SYW TJR SYW
September 26, 2003 event Total Intensity & E-W Keogram TIME (UT)
Finding one-to-one correspondenceTracing temporal variation of conjugate location
Satellite Observation IMAGE/FUV WIC and POLAR VIS Earth Camera Østgaardet al. (JGR, 2004) Longitudinal displacement depending on the clock angle
T – 8.3 minfor X= -10 Re Østgaardet al. (JGR, 2004) (X, Y, Z)gsm = (29.0~28.6, 11.1~12.5, 2.4~1.9) ReACE Vsw ~ 500 km/s IMF dataGeotail
Magnetic variation at Syowa and Tjornes 26-27 September, 2003 H(nT) TJR SYW TJR D(nT) SYW SYW Z(nT) TJR
+ Equivalent current & Ionospheric potential H TJR SYW D Z equivalent current &ionospheric potential TJR SYW B
IMF Bx Why BN < BS ? IMF Bx effect ? (Bx < 0 in this case) North-South asymmetry of magnetospheric configuration ? BN dB NP j|| N SP j|| S BS dB If BN < BS then NP could be located eastward of SP
Summary • The September 26, 2003 event is the best one in the 20 year history of the Syowa-Iceland conjugate auroral observation. • Extremely similar auroral activities were observed for more than 1 hour. • During the observation, the conjugate point moved about 200 km in longitude and about 50 km in latitude. • This movement cannot be explained only by the By or clock angle effect of the IMF. • North-south asymmetry of magnetospheric configuration could be a cause of the movement.
Vsw(km/s) B (nT) ACE By(nT) Bz(nT) ASY-D(nT) ASY-H(nT) SYM-H(nT) 14-29 September, 2003 Overview of the solar – geomagnetic condition
MH E W ML TJORNES September 26, 2003 eventAll-sky TV data (23:50:00~23:55:50 UT, 10 sec interval) SYOWA