T. Rollett, C. Möstl, M. Temmer, A. M. Veronig, C. J. Farrugia, H. K. Biernat
We present a new approach to combine remote observations and in situ data by
STEREO/HI and Wind, respectively, to derive the kinematics and propagation
directions of interplanetary coronal mass ejections (ICMEs). We used two
methods, Fixed-\Phi (F\Phi) and Harmonic Mean (HM), to convert ICME elongations
into distance, and constrained the ICME direction such that the ICME
time-distance and time-velocity profiles are most consistent with in situ
measurements of the arrival time and velocity. The derived time-velocity
functions from the Sun to 1 AU for the three events under study (1-6 June 2008,
13-18 February 2009, 3-5 April 2010) do not show strong differences for the two
extreme geometrical assumptions of a wide ICME with a circular front (HM) or an
ICME of small spatial extent in the ecliptic (F\Phi). Due to the geometrical
assumptions, HM delivers the propagation direction further away from the
observing spacecraft with a mean difference of ~25{\deg}.
View original:
http://arxiv.org/abs/1110.0300
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