Observations and Simulations of the Sun-to-Earth Evolution of a STEREO-Era Set of Earth-Impacting CMEs and their In Situ Magnetic Field
Abstract
Coronal mass ejections (CMEs) drive extreme space weather events throughout the solar system. Predicting the effects of a CME impact requires knowing not only if a CME will impact a given point, but also which part of the CME impacts, and what its magnetic properties are upon impact. We explore the relation between CME deflections and rotations, which change the position and orientation of a CME, and the resulting magnetic profiles at 1 AU. For 45 STEREO-era, Earth-impacting CMEs, we determine the region from which each CME erupts, reconstruct its coronal position and orientation, and perform a ForeCAT (Kay et al. 2015) simulation of the coronal deflection and rotation. From this large set of reconstructed and modeled CME deflections and rotations we determine variations in the behavior over the solar cycle as well as correlations with CME properties. We then couple the ForeCAT results with the FIDO in situ magnetic field model (Kay et al. 2017), allowing for comparisons with ACE and Wind observations. FIDO successfully reproduces the in situ magnetic field for all but three of the CMEs. From random walk best fits, we distinguish between ForeCAT's ability to determine FIDO's input parameters, and the limitations of using a simple flux rope model to reproduce complicated in situ structures. We find that the FIDO results are quite sensitive to changes of order a degree in the CME latitude, longitude, and tilt, suggesting that accurate space weather predictions require accurate measurements of a CME's position and orientation.
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2017)
- Pub Date:
- July 2017
- Bibcode:
- 2017shin.confE..20K