Inferring the Magnetic Field Configuration of an ICME From the In Situ Observations at Different Points

Abstract Interplanetary coronal mass ejections (ICMEs) would significantly influence the space environment when they encounter different planets, with their magnetic field configurations determining the level of such influences. Unfortunately, due to the lack of in situ observations, the magnetic field configurations of ICMEs in the heliosphere are only available at some special points. In this work, we present a novel model, called the Magnetic Field Configuration Inferring model, to reconstruct the magnetic field configuration of ICMEs using in situ observations from radial aligned observers. Originally, the model utilizes in situ magnetic field observations at a specified point as input data. A flux rope fitting model is applied to derive the magnetic field configuration at this point. Subsequently, the drag-based model and self-similar expansion assumption are incorporated to obtain the ICME parameters at the target point. Finally, the magnetic field configuration of the ICME at the target point is obtained based on the magnetic field and geometry parameters. We validate the model using two ICME events observed by Venus Express (VEX) and STEREO-A, showing the case of backcasting (STEREO-A to VEX) and forecasting (VEX to STEREO-A). The model results are well consistent with the observations except for some minor differences. These results demonstrate the model’s ability to infer the magnetic field configuration of ICMEs at different points in the heliosphere based on in situ observations from one specified point. The model can be useful for space weather forecasting, especially for space weather predictions on other planets.