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Y. C.-M. Liu, M. Opher, O. Cohen P.C.Liewer and T.I.Gombosi
A Simulation of a CME Propagation and Shock Evolution in the Lower Solar Corona Y. C.-M. Liu, M. Opher, O. Cohen P.C.Liewer and T.I.Gombosi George Mason University 01/03/2007
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Outline CME and Solar Energetic Particles Why Lower Solar corona?
Space Weather Modeling Framework Brief Introduction Simulations Background Solar Wind Initiate a CME Results Shock evolution, CME dynamics Conclusions
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CME and SEPs Stereo Modified from Lee, 2005
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Space Weather Modeling Framework
Inner Heliosphere (IH) Solar Corona (SC) 24 Rs 1AU Rs is solar radii
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MHD Equations
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Heating?- Parameterized by
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The Solar Wind CR 1922 solar minimum CR1922
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CME Initiation Loss of equilibrium!
The magnetic field under study is modeled by a force-free circular flux tube with the total current I, a pair of magnetic charges q and a line current I0. Below the photospheric plane. The flux tube is at force balance. Titov and Demoulin 1999
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The inserted TD flux rope
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Rising Flux Rope
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Bright Front and Dark Void
2D slice at Z=0.11 t=10 minutes
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Shock Speed and the background solar wind speed
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Why Acceleration? The acceleration determined by F=Ma
CME Pressures Drag Force Fd Gravity Sun The acceleration determined by F=Ma M=Mass_CME + Virtual Mass Fd=V2 Cd Forbes et al, 2006
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The Density Peak after the Shock
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Predicted and Modeled Acceleration
1 Cd=1, Mv=0; 2. Cd=tanhß, Mv=0; 3. Cd=1, considering Mv 4. Cd=tanhß, considering Mv, 5. Modeled acceleration
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The Forces
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Shock and Post Shock Compression Ratio
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New Progress Forbes 1995?
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More at: http://physics.gmu.edu/~yliuc/SWMF_Result
_MAY14_2007/PostAGU2007/2Dslices/2D_slice_MagneticEvolution.html
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Summary and Conclusions
We present the first detailed CME simulation in the lower solar corona using SWMF Shock is nearly perpendicular at the nose The acceleration of the CME is controlled by the pressure forces and the drag force. Magnetic pressure contributes to the acceleration at the bottom of the solar corona The post shock acceleration exists in 3-5 Rs and it could contribute to the particle acceleration The configuration near the sheath needs to be resolved.
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