Physics-based prediction of magnetic storms as driven by strong magnetic fields of coronal mass ejections (CMEs) is one of the most important and most difficult targets in the field of space weather. Daikou Shiota and Ryuho Kataoka are challenging this task as PSTEP’s members of Solar Storm Group (A02) and Geomagnetism Group (A03), respectively. They developed a new simulation of CMEs, which solves the propagation of complex magnetic fields from the Sun to the Earth in real time. This is a fundamental step to contribute to the next-generation operational space weather forecast as planned by PSTEP to mitigate the possible hazards originated from magnetic storms.
The propagation of CMEs was simulated based on magnetohydrodynamic equations and the observation-driven initial and boundary conditions of solar wind. A new and robust method to inject CMEs with internal twisted flux rope was developed and it utilizes solar observations of solar flares and CMEs. This is a new generation of CME model, which may enable us to predict the southward interplanetary magnetic field that can cause a magnetic storm on the Earth.
The results from the model using solar observational data from a series of CME events were successfully validated with in situ observations on the Earth’s orbit around Halloween of 2003. Owing to the inclusion of the flux rope mechanism we can predict the amplitude of the magnetic field within a CME that reaches the Earth, and accurately predicts its arrival time. The prediction using the new model will significantly contribute to accurately predicting magnetic fields in space and enhancing our understanding of the mechanisms behind CME events.
The article “Magnetohydrodynamic simulation of interplanetary propagation of multiple coronal mass ejections with internal magnetic flux rope (SUSANOO-CME)” was published in Space Weather, at doi:10.1002/2015SW001308
Figure Caption: A coronal mass ejection (CME) event showing a representation of the flux rope anchored at the sun and the propagation of the magnetic flux rope through space toward Earth. The white shaded lines indicate the magnetic field lines. Red shade indicates high-speed stream in the front of the CME.