Physics based modeling of extreme space weather

Major space weather events are caused by coronal mass ejections (CMEs) that typically travel to Earth in one to three days. These eruptions occur frequently, as often as several times per day during solar maximum, and cause geomagnetic storms by triggering sudden reconfigurations of the magnetosphere by magnetic reconnection. Extreme space weather events are caused by the most energetic CMEs, which drive sudden and extensive changes in the Earth's magnetic field producing among other effects, large-scale electric impulses that can melt transformers and cause cascading blackouts. Being able to predict extreme space weather is a challenging task, which requires both accurate simulations of CME structures when they reach Earth and the response of the magnetosphere. The magnetic reconnection process that lies at the heart of space weather events depends on the magnetic field carried by the coronal mass ejection as well as on the plasma processes happening on kinetic scales. Strong dayside reconnection is expected when the solar wind carries southward pointing interplanetary magnetic field (negative IMF BZ). Reconnection in the magnetotail can be either triggered by changes in the solar wind and IMF, or spontaneously. These events result in magnetic storms producing rapid changes in the magnetic and electric fields. Accurate modeling of magnetic storms therefore requires prediction of the interplanetary magnetic field of CMEs and an accurate model for the reconnection process. Our NSF PREEVENTS project addresses both of these crucial issues: (1) We work on providing a practical operation-ready method to predict the magnetic structure of the coronal mass ejection; and (2) We model the reconnection process with a validated kinetic model embedded into our global space weather model to provide quantitative assessments of the impacts of various extreme events.

In this presentation we will report on our progress with the second task.