Estimating the Magnetic Structure of an Erupting CME Flux Rope From AR12158 Using Data-Driven Modeling

Abstract

We investigate here the magnetic properties of a large-scale magnetic flux rope related to a coronal mass ejection (CME) that erupted from the Sun on September 12, 2014 and produced a well-defined flux rope in interplanetary space on September 14–15, 2014. We apply a fully data-driven and time-dependent magnetofrictional method (TMFM) using Solar Dynamics Observatory (SDO) magnetograms as the lower boundary condition. The simulation self-consistently produces a coherent flux rope and its ejection from the simulation domain. This paper describes the identification of the flux rope from the simulation data and defining its key parameters (e.g., twist and magnetic flux). We define the axial magnetic flux of the flux rope and the magnetic field time series from at the apex and at different distances from the apex of the flux rope. Our analysis shows that TMFM yields axial magnetic flux values that are in agreement with several observational proxies. The extracted magnetic field time series do not match well with in-situ components in direct comparison presumably due to interplanetary evolution and northward propagation of the CME. The study emphasizes also that magnetic field time-series are strongly dependent on how the flux rope is intercepted which presents a challenge for space weather forecasting.

Quantitative Characterization of Magnetic Flux Rope Properties for Two Solar Eruption Events

“…In addition, the current density distribution in Figure 10f at the intersections of a vertical slice with two field line bundles also shows less clearly-defined concentrations in those field-line regions. So different from the NLFFF extrapolation result by Zhao et al (2016) and the time-dependent magnetofrictional modeling result by Kilpua et al (2021), which demonstrated the existence of a strongly twisted MFR, we do not produce such a pre-existing MFR prior to the flare eruption for event 2.…”

“…The CMEs associated with the corresponding flares in these two events have been both observed by SOHO and STEREO spacecraft close to the peak times of the corresponding flares (Vemareddy & Zhang 2014;Cheng et al 2015;Cheng & Ding 2016;Joshi et al 2017). And the associated ICME/MC events were also observed by the WIND and ACE spacecraft at 1 au, which have been reported by Hu et al (2021a) and Kilpua et al (2021), respectively.…”

“…There was also a halo CME following the flare based on the observations from SOHO/LASCO and the coronagraph of STEREO B (data from STEREO A was unavailable during event 2). After two days, the WIND spacecraft encountered the subsequent ICME/MC structure at Earth (Kilpua et al 2021). Therefore, the connections of CME-MFRs from the Sun to Earth are well established for these two events.…”

Data-driven modeling of solar coronal magnetic field evolution and eruptions

“…All current data-driven models can be classified mainly into three groups with increasing degrees of complexity and, thus, realism. They are the magnetofrictional model, 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 the zero-β MHD model, 34 , 35 , 36 , 37 , 38 , 39 and the full MHD model. 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 The full MHD model can be divided into subclasses, such as isothermal, ideal, resistive, and full thermodynamic (including radiation and thermal conduction) models according to the different types of energy equations.…”

“…Kilpua et al. 25 analyzed the details of an MFR eruption in AR NOAA 12158 and attempted to compare its structure (but still in the source region) with in situ observations at 1 AU.

Figure 2 Synthetic images of coronal loops based on current density distribution from a data-driven magnetofrictional model for the evolution of AR NOAA 11158 (A–C) The same data from different viewing angles.

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