On the utility of flux rope models for CME magnetic structure below 30Rs
- 1Space Sciences Laboratory, University of California--Berkeley, Berkeley, CA 94720, USA (blynch@ssl.berkeley.edu)
- 2Space Science Center, University of New Hampshire, Durham, NH 03824, USA
- 3Predictive Science Inc., San Diego, CA 92121, USA
We present a comprehensive analysis of the three-dimensional magnetic flux rope structure generated during the Lynch et al. (2019, ApJ 880, 97) magnetohydrodynamic (MHD) simulation of a global-scale, 360 degree-wide streamer blowout coronal mass ejection (CME) eruption. We create both fixed and moving synthetic spacecraft to generate time series of the MHD variables through different regions of the flux rope CME. Our moving spacecraft trajectories are derived from the spatial coordinates of Parker Solar Probe’s past Encounters 7 and 9 and future Encounter 23. Each synthetic time series through the simulation flux rope ejecta is fit with three different in-situ flux rope models commonly used to characterize the large-scale, coherent magnetic field rotations observed in a significant subset of interplanetary CMEs (ICMEs). We present each of the in-situ flux rope model fits to the simulation data and discuss the similarities and differences in the model flux rope spatial orientations, field strengths, and magnetic flux content. We compare in-situ model properties to those calculated with the MHD data for both classic bipolar and unipolar ICME flux rope configurations as well as more problematic profiles such as those with a significant radial component to the flux rope axis orientation or profiles obtained with large impact parameters. We find general agreement among the in-situ flux rope fitting results for the classic profiles and much more variation among results for the problematic profiles. We also present a comparison between the MHD simulation data and the in-situ model flux ropes in a hodogram representation of the magnetic field rotation. We conclude that the in-situ flux rope models are generally a decent approximation to the field structure, but all the caveats associated with in-situ flux rope models will still apply (and perhaps moreso) at distances below 30Rs. We discuss our results in the context of future PSP observations of CMEs in the extended corona.
How to cite: Lynch, B., Al-Haddad, N., Yu, W., Palmerio, E., and Lugaz, N.: On the utility of flux rope models for CME magnetic structure below 30Rs, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6205, https://doi.org/10.5194/egusphere-egu22-6205, 2022.
