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Problems in Space Physics 長井嗣信 東京工業大学
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磁気圏の未解決問題 「いつも同じ話をしている」 1.容易に解決できそうだが 2.何が観測的に問題なのか 3.今後どうすべきか
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1.Substorm Onsets 2.Magnetic Storms 3.Plasma Convection
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1.Substorm Onsets Global Images Intense Ground Observation Network Mid-Tail Observations 10-30 Re Geosynchronous Orbit 6.6 Re
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L. A. Frank ICS-4 (1998) January 12, 1997 0726 UT
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Polar/UVI by A. Ieda0725:11 UT
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Polar/UVI January 12, 1997 0724:54 UT
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0725 UT
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0723 UT
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Gang Lu JGR 1999
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Gang Lu JGR 1999 70
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Kadokura (2002) SIT-TV at Syowa 427.8 nm
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Problems 1.Spatial Resolution 2.Time Resolution 3.UV 4.Magnetic Field Tracing 5.Conjugate Events
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L. R. Lyons et al. JGR 2001
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L. R. Lyons et al., JGR 2001
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10E 71.3 E 105E 141 E 192.5 E 322.5E Geographic Longitude Geomag. Lat. 1.5 -8.3 -10.4 -8.7 -1.1 8.6
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Global Satellite Aurora Images Spatial Resolution Time Resolution UV Comparison with Ground Observations Geosynchronous Substorm Signatures Longitudinal Effect Particles or Magnetic Field
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McPherron 1991Kamide and Baumjohann 1993
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Burton et al., 1975 2.Magnetic Storms
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Ring Current Modeling Ebihara et al. 2001, 2002
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Strangeway and Johnson 1983
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Strangeway and Johnson 1983
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Strangeway and Johnson 1983
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Magnetic Storms 1.Solar wind parameters Dst 2.Ring current modeling (dipole field) Dst 3.H+ vs. O+ 4.What should be known? Particle distributions Time, Position (L, MLT, Latitude) Energy, Species
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3. Plasma Convection Plasma Transport = Field Transport Pictures from Ground Observations Pictures from Tail Observations
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Polar Cap Potential Drop 100 kV Polar Cap > 75 degrees L = 2 x 3.14 x 6371.2 x 30/360 = 3300 km E = 100kV / 3300km = 30 mV/m B = 60000 nT V = E/B = 30 mV/m / 60000 nT = 500 m/s T = 3300km / 500 m/s = 100 min Vsw = 500 km/s T = 100 Re/500 km/s = 20 min
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Nishitani et al. JGR 2001
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Plasma Convection in the Tail Stationary vs Bursty Paterson et al. JGR 1998 100 Re/10 km/s = 1000 min Angelopoulos et al. 1999
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A dipolarization at 10 Re (for a substorm)
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Mid- and Near-Tail Plasma Observations 1.Plasmas are NOT MHD 2.Problems in the Present Instruments No Convincing Observations
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今後の方向 1.確かに進歩 2.新たな問題 3.根本的な問題 将来計画 1.対象の明確化(絞込み) 2.何が必要とされているか 3.対象にあった観測 機械と軌道
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4.IMF Bz Control for the Plasma Sheet 1.IMF Bz > 0 (northward) 2.IMF Bz < 0 (southward) 3.ssc (density increase in SW)
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IMF Bz Effect Substorms IMF Bz Northward Turning > 50% IMF Bz > 0 Substorm Processes Prolonged IMF Bz Periods Cold and Dense Plasmas Stationary
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Summary 1.Importance of Ground Observations Optical Aurora 2.Ionospheric Signatures North / South Conjugate 3.IMF Bz Control Drastic Changes
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Future Mission SCOPE (Scale Coupling in Plasma Environment) 1.High time resolution in particle observations 2.Full energy coverage in particle observations 3.Multi-point observations to know the s/c location relative to the neutral line
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