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| Titel |
Testing ElEvoHI on a multi-point in situ detected Coronal Mass Ejection |
| VerfasserIn |
Tanja Amerstorfer, Christian Möstl, Phillip Hess, M. Leila Mays, Manuela Temmer |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143909
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| Publikation (Nr.) |
 EGU/EGU2017-7675.pdf |
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| Zusammenfassung |
| The Solar TErrestrial RElations Observatory (STEREO) has provided us a deep insight into
the interplanetary propagation of coronal mass ejections (CMEs). Especially the
wide-angle heliospheric imagers (HI) enabled the development of a multitude of
methods for analyzing the evolution of CMEs through interplanetary (IP) space.
Methods able to forecast arrival times and speeds at Earth (or other targets) use
the advantage of following a CME’s path of propagation up to 1 AU. However,
these methods were not able to reduce today’s errors in arrival time forecasts to less
than ±6 hours, arrival speeds are mostly overestimated by some 100 km s−1. One
reason for that is the assumption of constant propagation speed, which is clearly
incorrect for most CMEs—especially for those being faster than the ambient solar
wind.
ElEvoHI, the Ellipse Evolution model (ElEvo) based on HI observations, is a new
prediction tool, which uses the benefits of different methods and observations. It provides the
possibility to adjust the CME frontal shape (angular width, ellipse aspect ratio)
and the direction of motion for each CME event individually. This information
can be gained from Graduated Cylindrical Shell (GCS) flux-rope fitting within
coronagraph images. Using the Ellipse Conversion (ElCon) method, the observed HI
elongation angle is converted into a unit of distance, which reveals the kinematics of
the event. After fitting the time-distance profile of the CME using the drag-based
equation of motion, where real-time in situ solar wind speed from 1 AU is used as
additional input, we receive all input parameters needed to run a forecast using the
ElEvo model and to predict arrival times and speeds at any target of interest in IP
space.
Here, we present a test on a slow CME event of 3 November 2010, in situ detected by
the lined-up spacecraft MESSENGER and STEREO Behind. We gain the shape
of the CME front from a cut of the 3D GCS CME shape with the ecliptic plane,
resulting in an almost ideal ElEvoHI forecast of arrival time and speed at 1 AU. |
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