cme propagation csi 769 / astr 769 lect. 11, april 10 spring 2008
DESCRIPTION
CME MSOE Model Siscoe, G.L., Crooker, N.U., Elliott, H.A., “Initial-Condition Influences on CME Expansion and Propagation” Solar Physics, Vol. 239, , DOI: /s , 2006 MSOE: Melon-Seed-Overpressure-Expansion ModelTRANSCRIPT
CME Propagation
CSI 769 / ASTR 769 Lect. 11, April 10 Spring 2008
CME Flux Rope ModelLepping, R.P., Jones, J.A., Burlaga.“Magnetic Field Structure of Interplanetary Magnetic Clouds at 1 AU”JGR, Vol. 95, No. A8, 11957-11965, 1990
CME MSOE ModelSiscoe, G.L., Crooker, N.U., Elliott, H.A., “Initial-Condition Influences on CME Expansion and Propagation”Solar Physics, Vol. 239, 293-316, DOI: 10.1007/s11207-006-0302-3, 2006
MSOE: Melon-Seed-Overpressure-Expansion Model
Interplanetary CME (ICME)•CME propagates into the interplanetary space, plowing through the ambient solar wind•The magnetic structure of ICME at 1 AU is similar to that in its solar origin, which is highly helical (called flux rope)•At 1 AU, it is called magnetic cloud
•highly organized magnetic field is observed, e.g., smooth rotation•Large scale, crossing the Earth for ~ 24 hours
Magnetic Cloud
ICME Identification Dst
B/Bz
Vel
Np
TpTexp
β
Sun
2004/07/27 storm (-182 nT)
Shock Front: discontinuity
ICME (ejecta): • B enhance• Bz rotation• Low Plasma β• Low Tp• High QFe
• -----
SH (Shock Sheath)
Solar Sources
Solar Wind: BimodalFast wind originates from coronal hole,
Slow wind originates from regions close to streamer belts or heliospheric current sheet
SW heliographic latitudinalDistribution (Ulysses observation)
Corotating Interaction Region (CIR)•When a low latitude coronal hole appears (across the heliographic equator), fast wind exists in the ecliptic plane.
Corotating Interaction Region (CIR)•The jetline of fast wind is less curved than that of slow wind•Fast streams “catching up” with slow streams, compressing the preceding stream and produce a high pressure region.•The interaction region is at the leading edge of the fast stream•Since low-latitude coronal holes can live over several solar rotations, this structure can recur several times•This is commonly called “corotating interaction region” or CIR•A pair of forward and reverse shocks forms
CIRCorotating Interaction Region: Caused by the interaction of fast SW originated from
coronal hole with preceding slow SW CIR/SI
IMF
The End