problems in space physics
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Problems in Space Physics. 長井嗣信 東京工業大学. 磁気圏の未解決問題 「いつも同じ話をしている」 容易に解決できそうだが 何が観測的に問題なのか ３．今後どうすべきか. Substorm Onsets Magnetic Storms Plasma Convection. Substorm Onsets Global Images Intense Ground Observation Network Mid-Tail Observations 10-30 Re - PowerPoint PPT PresentationTRANSCRIPT
Problems in Space Physics
長井嗣信東京工業大学
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
1. Substorm Onsets
2. Magnetic Storms
3. Plasma Convection
1. Substorm Onsets
Global Images
Intense Ground Observation Network
Mid-Tail Observations 10-30 Re
Geosynchronous Orbit 6.6 Re
L. A. Frank ICS-4 (1998)
January 12, 1997 0726 UT
Polar/UVI by A. Ieda 0725:11 UT
Polar/UVI January 12, 1997
0724:54 UT
0725 UT
0725 UT
0723 UT
Gang LuJGR 1999
Gang LuJGR 1999
70
70
Kadokura (2002)SIT-TV at Syowa427.8 nm
Problems
1. Spatial Resolution2. Time Resolution3. UV4. Magnetic Field Tracing5. Conjugate Events
L. R. Lyons et al. JGR 2001
L. R. Lyons et al., JGR 2001
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
Global Satellite Aurora Images
Spatial ResolutionTime ResolutionUV
Comparison with Ground Observations
Geosynchronous Substorm Signatures
Longitudinal Effect Particles or Magnetic Field
McPherron 1991 Kamide and Baumjohann 1993
Burton et al., 1975
2. Magnetic Storms
Ring Current Modeling
Ebihara et al. 2001, 2002
Strangeway and Johnson 1983
Strangeway and Johnson 1983
Strangeway and Johnson 1983
Magnetic Storms
1. Solar wind parameters Dst2. Ring current modeling (dipole field) Dst3. H+ vs. O+4. What should be known?
Particle distributionsTime, Position (L, MLT, Latitude)Energy, Species
3. Plasma Convection
Plasma Transport = Field Transport
Pictures from Ground Observations
Pictures from Tail Observations
Polar Cap Potential Drop 100 kVPolar Cap > 75 degrees L = 2 x 3.14 x 6371.2 x 30/360 = 3300 kmE = 100kV / 3300km = 30 mV/mB = 60000 nT V = E/B = 30 mV/m / 60000 nT = 500 m/sT = 3300km / 500 m/s = 100 min
Vsw = 500 km/sT = 100 Re/500 km/s = 20 min
Nishitani et al. JGR 2001
Plasma Convection in the Tail
Stationary vs Bursty
Paterson et al. JGR 1998
100 Re/10 km/s = 1000 min Angelopoulos et al. 1999
A dipolarization at 10 Re (for a substorm)
Mid- and Near-Tail Plasma Observations
1. Plasmas are NOT MHD
2. Problems in the Present Instruments
No Convincing Observations
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
4. IMF Bz Control for the Plasma Sheet
1. IMF Bz > 0 (northward)
2. IMF Bz < 0 (southward)
3. ssc (density increase in SW)
IMF Bz Effect
SubstormsIMF Bz Northward Turning > 50%IMF Bz > 0 Substorm Processes
Prolonged IMF Bz PeriodsCold and Dense PlasmasStationary
Summary
1. Importance of Ground ObservationsOptical Aurora
2. Ionospheric SignaturesNorth / South Conjugate
3. IMF Bz ControlDrastic Changes
Future Mission
SCOPE (Scale Coupling in Plasma Environment)
1. High time resolution in particle observations2. Full energy coverage in particle observations3. Multi-point observations to know the s/c location relative to the neutral line