cas key laboratory of geospace environment, ustc the deflection of 2008 september 13 cme in...
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CAS Key Laboratory of Geospace Environment, USTC
The Deflection of 2008 September 13 CME in Heliosphere Space
ISEST, Hvar, Croatia,2013 June 17
Collaborators: Boyi Wang, Yuming Wang, Fang Shen, Pinzhong Ye , Shui Wang
CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science &
Technology of China, Hefei, Anhui 230026, China
Chenglong Shen
1. Introduction
Make the limb(back) or high latitude CME hit Earth ➨ miss alert ➨ A possible reason for "problematic" ICMEs
Make the Earth direct CME miss Earth
➨wrong alert
Deflection of CMEs may significant influence their geoeffectiveness!
Deflection in meridian plane1. DIrect observed from coronagraph ➨ from high latitude region to equator
2. Widely reported and studied[e.g. MacQueen et al,1986, Gopalswamy et al., 2003, Cremades and Bothmer, 2004, Kilpua et al., 2009; Shen et al., 2011, Gui et al., 2011;Wang et al., 2011]
Wang et al., 2011
Deflection in ecliptic plane
1. Can not be direct observed before STEREO, but suggested by Wang et al., [2004]
2. Reported by some authors after STEREO[e. g. Gopalswamy et al., 2009;Gui et al., 2011; Poomvised et al., 2012; Temmer et al., 2012; Liu et al., 2012]
Deflection caused by CME interaction1. Could be direct observed by coronagraph[Gopalswamy et al., 2001]
2. Reported by recent work using STEREO observation[e. g. Shen et al., 2012, Lugaz et al., 2012]
➣ Magnetic Field Frozen-In, MFFI[Wang et al., 2004, Wang et al., 2006]
Source: Background solar windProperties:Fast CME -------> Deflect to EastSlow CME ------> Deflect to WestApplication:➨East-West asymmetry of the source of Earth arrival CME[Wang et al., 2004]
➨Geoeffectiveness of 2005 September CMEs[Wang et al., 2006]
Wang et al., 2004
Different explanation and models about the deflection
➣ Coronal Hole Model[Cremades and Bothmer, 2004 ;Gopalswamy et al., 2009]
Source: ➨Coronal holeProperties:Coronal holes push the CME awayApplication:➨`driverless’ shock in in-situ observations[Gopalswamy et al., 2009]
Gopaslwamy et al., 2009
➣ Magnetic energy density gradient model[e.g. Shen et al., 2011,Gui et al., 2011]
Source: ➨Background magnetic fieldProperties:➨CME deflect to lower magnetic energy density regionObservation results:➨CME would propagated along the current sheet➨Mainly happened <5RsShen et al., 2011
Gui et al., 2011
2.Coronagraph Observations
A halo CME in STB A east limb CME in STA
It is possible that this CME propagated east to the Sun-Earth line and direct to STB!
From GCS model: ➨ Very slow CME
➨ Direct to STB at beginning➨ Continuously deflect to West from 05:00UT Sep 13 (>10Rs)
3.In-situ observations
From in-situ observations:➨ A ICME arrived Earth No full halo CME from September 9 to September 14---->"problematic" ICMEs?
➨ A ICME flank possible swept STB
Method Arrival Time:
Direct Triangulation[Liu et al. 2009]
September 1700:02UT
HM Triangulation[Lugaz et al., 2009]
September 1618:05UT
ObservationsSeptember 1704:00UT
From interplanetary observations:
➨This CME did deflect to west during its propagation in heliosphere and make this east limb CME (seen from SOHO) arrived the Earth
5. Conclusion and discussionA full store of a CME’s deflect in heliosphere from Sun to 1AU is reported.
Why deflection happened?
➨ Solar wind
➨ Background magnetic field happened in the region >5 Rs -----> not for this event ➨ Coronal Hole
no obvious coronal hole -----> not for this event
A website of the full halo CMEs ( now from 2007 March 1 to 2012 May 31, will be updated continuously).
http://space.ustc.edu.cn/dreams/fhcmes/