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Bastille Day 2000 Solar Energetic Particles Event: Ulysses observations at high heliographic latitudes M. Zhang Florida Institute of Technology
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Flare Earth Ulysses Ulysses field footpoint CME Earth field footpoint Ulysses at 3.AU 62 o S on July 14, 2000 Location, Location, Location
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Ulysses at 2.7 AU, 70 o S
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Small latitude gradient of cosmic ray Recurrent cosmic ray modulation effects by CIR’s propagate to the polar regions above 80 o Energetic articles accelerated by CIR shocks appear in the polar regions above 80 o Evidence for easy latitudinal transport of energetic particles in the heliosphere Ulysses observations during 1994-1995 solar minimum: Ulysses observations during 2000-2001 solar maximum: Zero latitude gradient of cosmic ray Solar energetic particles from same solar events are observed by spacecraft (Ulysses and IMP-8) in large latitude and longitude separations.
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How do the solar energetic particles get to high latitudes? 1.Direct magnetic connection to particle sources (particle transport along field lines) Extended particle source in the corona Field lines connect to low latitude 2.Cross-field transport Anything is possible
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Ulysses COSPIN/HET Sectored 40-90 MeV Proton Rates
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Possible sources of first-order anisotropy perpendicular to magnetic fields 1. Compton-Getting effect: A 1 < 4% E>40 MeV, < ~2 V sw = 600 km/s No 2. B x Gradient (drift effect): A 1 is small ( r g =0.003 AU) Magnetic polarity No 3. Diffusion: Yes
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Conclusion Easy particle transport across heliographic latitude Perpendicular diffusion flow was observed Implication to particle scattering theory
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