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Title: THE DEFLECTION OF THE TWO INTERACTING CORONAL MASS EJECTIONS OF 2010 MAY 23-24 AS REVEALED BY COMBINED IN SITU MEASUREMENTS AND HELIOSPHERIC IMAGING

Journal Article · · Astrophysical Journal
;  [1]; ;  [2];  [3];  [4];  [5]
  1. Space Science Center, University of New Hampshire, Durham, NH (United States)
  2. RAL Space, STFC Rutherford Appleton Laboratory, Chilton (United Kingdom)
  3. Space Science Laboratory, University of California, Berkeley, CA (United States)
  4. Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming 650011, Yunnan (China)
  5. Kanzelhoehe Observatory-IGAM, Institute of Physics, University of Graz, A-8010 Graz (Austria)

In 2010 May 23-24, Solar Dynamics Observatory (SDO) observed the launch of two successive coronal mass ejections (CMEs), which were subsequently tracked by the SECCHI suite on board STEREO. Using the COR2 coronagraphs and the heliospheric imagers (HIs), the initial direction of both CMEs is determined to be slightly west of the Sun-Earth line. We derive the CME kinematics, including the evolution of the CME expansion until 0.4 AU. We find that, during the interaction, the second CME decelerates from a speed above 500 km s{sup -1} to 380 km s{sup -1}, the speed of the leading edge of the first CME. STEREO observes a complex structure composed of two different bright tracks in HI2-A but only one bright track in HI2-B. In situ measurements from Wind show an 'isolated' interplanetary CME, with the geometry of a flux rope preceded by a shock. Measurements in the sheath are consistent with draping around the transient. By combining remote-sensing and in situ measurements, we determine that this event shows a clear instance of deflection of two CMEs after their collision, and we estimate the deflection of the first CME to be about 10 Degree-Sign toward the Sun-Earth line. The arrival time, arrival speed, and radius at Earth of the first CME are best predicted from remote-sensing observations taken before the collision of the CMEs. Due to the over-expansion of the CME after the collision, there are few, if any, signs of interaction in in situ measurements. This study illustrates that complex interactions during the Sun-to-Earth propagation may not be revealed by in situ measurements alone.

OSTI ID:
22086447
Journal Information:
Astrophysical Journal, Vol. 759, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
Country of Publication:
United States
Language:
English