CMEs in the Heliosphere: III. A Statistical Analysis of the Kinematic Properties Derived from Stereoscopic Geometrical M
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CMEs in the Heliosphere: III. A Statistical Analysis of the Kinematic Properties Derived from Stereoscopic Geometrical Modelling Techniques Applied to CMEs Detected in the Heliosphere from 2008 to 2014 by STEREO/HI-1 D. Barnes1 · J.A. Davies1 · R.A. Harrison1 · J.P. Byrne1 · C.H. Perry1 V. Bothmer2 · J.P. Eastwood3 · P.T. Gallagher4,5 · E.K.J. Kilpua6 · C. Möstl7 · L. Rodriguez8 · A.P. Rouillard9 · D. Odstrˇcil10
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Received: 23 June 2020 / Accepted: 10 October 2020 © The Author(s) 2020
Abstract We present an analysis of coronal mass ejections (CMEs) observed by the Heliospheric Imagers (HIs) onboard NASA’s Solar Terrestrial Relations Observatory (STEREO) spacecraft. Between August 2008 and April 2014 we identify 273 CMEs that are observed simultaneously, by the HIs on both spacecraft. For each CME, we track the observed leading edge, as a function of time, from both vantage points, and apply the Stereoscopic SelfSimilar Expansion (SSSE) technique to infer their propagation throughout the inner heliosphere. The technique is unable to accurately locate CMEs when their observed leading edge passes between the spacecraft; however, we are able to successfully apply the technique to 151, most of which occur once the spacecraft-separation angle exceeds 180◦ , during solar maximum. We find that using a small half-width to fit the CME can result in inferred acceleration to unphysically high velocities and that using a larger half-width can fail to accurately locate the CMEs close to the Sun because the method does not account for CME
B D. Barnes
[email protected]
1
STFC RAL Space, Rutherford Appleton Laboratory, Harwell Campus, Oxfordshire, OX11 0QX, UK
2
Institue for Astrophysics, University of Göttingen, 37077 Göttingen, Germany
3
Blackett Laboratory, Imperial College London, SW7 2AZ, UK
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School of Physics, Trinity College Dublin, Dublin 2, Ireland
5
School of Cosmic Physics, Dublin Institute for Advanced Studies, Dublin 2, Ireland
6
Department of Physics, University of Helsinki, PO Box 64, 00014, Helsinki, Finland
7
Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria
8
Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium
9
Institut de Recherche en Astrophysique et Planétologie, 9 Ave. du Colonel Roche, 31028 Toulouse Cedex 4, France
10
School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030-4444, USA
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over-expansion in this region. Observed velocities from SSSE are found to agree well with single-spacecraft (SSEF) analysis techniques applied to the same events. CME propagation directions derived from SSSE and SSEF analysis agree poorly because of known limitations present in the latter. Keywords Coronal mass ejections · Heliosphere · Space weather
1. Introduction In addition to the continuous outflow of the solar wind, coronal mass ejections (CMEs: e.g. Webb and Howard, 2012) are a phenomenon by which the Sun releases large quantities of energy in the for
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