The aims of this project was to use numerical simulations to study the energy transfer between the solar wind and the Earth's magnetosphere. The three science questions set were (1) to resolve where along the magnetospheric boundary (magnetopause) energy transfer occurs, (2) how solar wind fluctuations impact the boundary processes, and (3) how small-scale kinetic effects impact the energy transfer processes.

(1) The energy transfer across the magnetopause was studied focusing especially on periods of geomagnetic storms, when significant energy transport from the solar wind driver explosive and longer-term variations in the Earth's space environment. It was found that at all times, there is significant energy outflow and inflow, and the net energy input from the solar wind is the difference of the input and output - and always much smaller than either one separately. This led to the discovery of the importance of the internal magnetospheric state on defining when and where energy flows (figure 1).

(2) Higher-frequency solar wind fluctuations were shown to have a relatively minor role in the energy transport, while they can penetrate the boundary and cause other dynamic processes. However, lower-frequency fluctuations were shown to have an important impact on where and when in the Earth's magnetotail explosive reconnection processes occur - these are the processes that cause space weather hazards closer to the Earth.

(3) The small-scale effects were studied using the Vlasiator code. We showed that when the boundary is modeled with sufficient resolution and kinetic effects, it develops small-scale flux transfer events, which travel across the boundary and dominate the energy transport. The first-ever kinetic simulations covering the entire magnetosphere were run, and shown to develop multiple instabilities contributing to the energy transport and dissipation processes (figure 2).  

The project involved a doctoral student, whose thesis on solar wind - magnetosphere energy transfer was completed. They will continue as a postdoc for another year to follow interesting new research avenues found during the thesis. He also has developed initial collaboration with the US Space Force to use the models in space weather prediction and education.

The project involved two post-doctoral scientists. One will transfer to a next postdoc position, while the other one transitioned to a research scientist position.  

The project methodologies are included in the Space Weather Modeling Framework, and will be available for other researchers and space weather forecasters to use. The simulations are freely available. The results were published in several scientific articles and numerous conference presentations.

This research has been conducted in close collaboration with the National Science Foundation Geospace Environment Modeling (GEM) community. This work has contributed to several of the focus groups, most notably on those focusing on dayside kinetic processes in global solar wind - magnetosphere interaction, and magnetic reconnection in the age of the Heliophysics System Observatory. The project results have been presented biannually at the summer workshop and mini-meeting held in conjunction with the American Geophysical Union meeting.

Last Modified: 12/18/2023
Modified by: Tuija I Pulkkinen