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A STUDY OF THE KINEMATIC EVOLUTION OF CORONAL MASS EJECTIONS J
A STUDY OF THE KINEMATIC EVOLUTION OF CORONAL MASS EJECTIONS J. Zhang,1 K. P. Dere,2 R. A. Howard,2 and A. Vourlidas2 The Astrophysical Journal, 604: , 2004 March 20 太陽雑誌会 2004/6/7 殿岡
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Introduction the kinematic evolution of CMEs.
Zhang et al (Paper I) described the kinematic evolution of impulsive CMEs. Two classes of CME kinematic behavior, impulsive and gradual CMEs. the full kinematic evolution of 3 CME events based LASCO C1/C2/C3,to demonstrate the diversity of CME kinematic properties: impulsive, grdual and intermediate CME.
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2. OBSERVATIONS AND DATA ANALYSIS
LASCO C1, C2, and C3 GOES X-ray 1--8 full-disk flux as flare input LASCO C1.. before SOHO interruption in 1998. Height plot of C1 and C2/C3 .. leading edge only. The uncertainity at 8 pxels in each image. numerical derivative method CME mass measurement.
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3.1. CME 1: Impulsive Acceleration Figure1
1998 June 11 event. GOES M1.4 class flare A case of Impulsive acceleration event. C1 FOV .. asymmetric expanding. C2/C3 FOV .. symmetric around the equator. different shape.
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3.1. CME 1: Impulsive Acceleration Figure2
(2b) 3phase of kinematic evlution. initiation phase.. <100km/s, about 1hr accelaration phase .. velocity increase, last for about min. propagation phase CME velocity vs X-ray flux, acceleration vs X-ray flux derivative.
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3.2. CME 2: Intermediate Acceleration Figure3
2000October 25 event, no C1. Intermiediate acceleration event. GOES C4.0 flux level long-rise, long-fall event in X-ray. 160min for rise phase.
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3.2. CME 2: Intermediate Acceleration Figure4
peak speed .. ~CME1 acceleration times smller than CME1 longer duration x CME velocity vs X-ray flux.. good temporal correlation for the longer rise time event.
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3.3. CME 3: Gradual Acceleration Figure5
1997 October 19 Very weak but persistent accelation and slow velocity event. no apparent GOES flare
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3.3. CME 3: Gradual Acceleration Figure6
time range is 32hr, longer than previous 2 events. No impulsive or fast acceleratoin phase. a velocity plateau for 5 hr measurement gap between 05 and 08 ut.
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3.4. Summary of Results: Figure7
V-T plot.. CME 1 and 2 are similar
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Table1
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4. DISCUSSIONS 4.1. CME Kinematics
3 parameters to characerize a CMEs accelatation: duration, magnitude, distance. impulsive accelaration – short duration, very weak accelaration – long duration. Most CME events may reside in between the extremely impulsive ones and the gradual ones. CME acceleration in the acceleration phase can vary by 3 orders of magnitude, duration can also vary by the same magnitude.
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4. DISCUSSIONS 4.1. CME Kinematics
There is no compelling statistical evidence to support this classification. The statistical distribution of CME velocity always shows a continuous Gaussian distribution and shows no sign of a bimodal pattern. The average acceleration in the outer corona has Gaussian- like distribution. a large number of events observatin is rquired. two-class CME classification is oversimlified.
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4.2. Relationship between CMEs and Flares
correlation between CME velocity profiles and soft X-ray flux profile, also for their derivatives. CMEs and flares are physically integrated phenomena. CME location X-ray particle acceleration vs CME property. particle acceleration and large-scale CME acceleration are phusically related.
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5. CONCLUSIONS property of 3 CMEs
CME acceleration can vary by 3 orders of magnitude from several m s -2 to several thousand m s -2, while the acceleration duration can also vary. CME larrge-scale acceleration and flare particle acceleration are driven by the same physical process or by multiple processes that are physicaly coupled in the corona.
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