Study of CME Propagation in the Inner Heliosphere: SOHO LASCO, SMEI and STEREO HI Observations of the January 2007 Events

Solar Physics 256 (2), 239−267, 2009

Study of CME Propagation in the Inner Heliosphere: SOHO LASCO, SMEI and STEREO HI Observations of the January 2007 Events

D.F. Webb
Inst. for Scientific Research, Boston College, Chestnut Hill, MA, USA
Air Force Research Lab., Space Vehicles Directorate, Hanscom AFB, MA, USA

T.A. Howard
Air Force Research Lab., National Solar Obs., Sunspot, NM, USA

C.D. Fry
Exploration Physics Intl, Inc., Huntsville, AL, USA

T.A. Kuchar
Inst. for Scientific Research, Boston College, Chestnut Hill, MA, USA
Air Force Research Lab., Space Vehicles Directorate, Hanscom AFB, MA, USA

D. Odstrcil
Cooperative Inst. for Research in Environmental Sciences, Univ. of Colorado, Boulder, CO, USA

B.V. Jackson and M.M. Bisi
Cntr for Astrophysics and Space Science, Univ. of California San Diego, La Jolla, CA, USA

R.A. Harrison
Space Physics Division, Space Science and Technology Dept., Rutherford Appleton Labo., Chilton, UK

J.S. Morrill and R.A. Howard
Space Science Division, Naval Research Lab., Washington, DC, USA

J.C. Johnston
Air Force Research Lab., Space Vehicles Directorate, Hanscom AFB, MA, USA

Abstract

We are investigating the geometric and kinematic characteristics of interplanetary coronal mass ejections (ICMEs) using data obtained by the LASCO coronagraphs, the Solar Mass Ejection Imager (SMEI), and the SECCHI imaging experiments on the STEREO spacecraft. The early evolution of CMEs can be tracked by the LASCO C2 and C3 and SECCHI COR1 and COR2 coronagraphs, and the HI and SMEI instruments can track their ICME counterparts through the inner heliosphere. The HI fields of view (4 – 90°) overlap with the SMEI field of view (>20° to all sky) and, thus, both instrument sets can observe the same ICME. In this paper we present results for ICMEs observed on 24−29 January 2007, when the STEREO spacecraft were still near Earth so that both the SMEI and STEREO views of large ICMEs in the inner heliosphere coincided. These results include measurements of the structural and kinematic evolution of two ICMEs and comparisons with drive/drag kinematic, 3D tomographic reconstruction, the HAFv2 kinematic, and the ENLIL MHD models. We find it encouraging that the four model runs generally were in agreement on both the kinematic evolution and appearance of the events. Because it is essential to understand the effects of projection across large distances, that are not generally crucial for events observed closer to the Sun, we discuss our analysis procedure in some detail.