2004 Fiscal Year Final Research Report Summary
Conjugate auroral observation during solar maximum
| Project/Area Number |
13573007
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | National Institute of Polar Research |
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Principal Investigator |
SATO Natsuo National Institute of Polar Research, Division for Research and Education, Professor, 研究教育系, 教授 (50132709)
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| Co-Investigator(Kenkyū-buntansha) |
EJIRI Masaki National Institute of Polar Research, Division for Research and Education, Professor, 研究教育系, 教授 (30013692)
KADOKURA Akira National Institute of Polar Research, Division for Research and Education, Associate Professor, 研究教育系, 助教授 (70185883)
NISHINO Masanori Nagoya Univ. Solar Terreetrial Environmental Laboratory, Associate Professor, 太陽地球環境研究所, 助教授 (70023679)
MAKITA Kazuo Takusyoku Univ., School of Engineering, Professor, 工学部, 教授 (40129945)
TONEGAWA Yutaka Tokai Univ., School of Engineering, Professor, 工学部, 教授 (80188763)
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| Project Period (FY) |
2001 – 2004
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| Keywords | aurora / geomagnetic conjugate / Antarctica / Iceland / ionosphere / magnetosphere / solar eclipse / Syowa Station |
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| Research Abstract |
Charged particles in the Earth's magnetosphere are basically constrained to move along geomagnetic field lines. Thus the bright night-time auroras that are caused by electrons accelerated towards Earth are visible mapping of the geomagnetic field lines. Interhemispheric conjugate auroras provide a unique opportunity to examine how and where the geomagnetic field lines connect the two hemispheres. Syowa Station in Antarctica and stations in Iceland form an ideal set of observatories to study geomagnetically conjugate optical auroras in the auroral zone. A campaign of conjugate auroral observations using all-sky TV cameras has been carried out during equinox season since 1984 during the equinox period.
In this study during last 4 Years we found following interesting results; 1 we found extremely similar interhemispheric conjugate auroras observed with all-sky TV cameras at Syowa in Antarctica and Tjornes in Iceland. During this event, meso-scale discrete auroras including both east-west a
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nd north-south directed auroral forms, showed quite similar shapes, movements and luminosity variations at both observatories. Using these data we were able to trace the temporal movements and displacement of auroras in the northern and southern hemispheres with a high spatial-temporal resolution. Our results indicate that the geomagnetic conjugate point of one station moved 〜200 km in longitude and 〜50 km in latitude during an hour, 2) we have carried out a direct comparison of pulsating auroras observed from the ground at Syowa in Antarctica and onboard the FAST satellite together with conjugate-pair observations on the ground at the Syowa and Iceland observatories. Combining high resolution measurements made by the FAST satellite with simultaneous conjugate optical observations on the ground we were able to resolve spatial and temporal ambiguities associated with the observed pulsating auroral phenomena. Using the data we have firstly proposed generation region of pulsating auroras, 3) A total eclipse of the Sun was observed in Antarctica on 23 November 2003. The total eclipse zone crossed the Antarcic continent poleward of Syowa Station (69.0 deg. S, 39.6 deg. E) at a minimum distance of 600 km from the station. This astronomical event is a unique opportunity to examine how the solar eclipse affects the ionosphere, not only in the Southern Hemisphere but also in the conjugate Northern Hemisphere. The magnetometer data showed that ion ospheric disturbances occurred in both hemispheres at the time of the solar eclipse. It is interesting to note that spike-like magnetic impulses occurred at Syowa at all stations in Iceland and some observatories in Scandinavia at the time of maximum eclipse at Syowa (〜23:00 UT). This suggests that ionosphere-magnetosphere couplings were activated in both hemispheres by the localized darkness in the Southern Hemisphere. Less
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