Space physics

In space physics our key research focuses are the evolution and propagation of coronal mass ejections (CMEs) from Sun to Earth, interaction of the solar wind with the near-Earth space environment, and interplanetary shock waves. We develop models and analyze observations from several ESA and NASA spacecraft. Solar wind-magnetosphere coupling is studied within Academy of Finland Consortium SWIFT with the School of Electrical Engineering of Aalto University. SWIFT aims at quantifying the importance of solar wind fluctuations and magnetotail processes in space weather driving. CME evolution is studied within the FP7 HELCATS project (led by Rutherford  Appleton Laboratory, UK). HELCATS focuses on heliospheric imaging of CMEs and connecting these remote sensing observations with in-situ CME properties. Highlight of 2014 were the analysis of extreme solar storms (published in Nature Communication), investigation how large-scale solar wind drivers can explain dramatic variations in the Van Allen radiation belts and the compilation of the first version of the heliospheric shock database. Our work with extreme storms gave new insight on how solar superstorms form and propagate with minimum deceleration in the inner heliosphere. The key finding is the interaction of multiple strong CMEs immediately after their launch and preconditioning of the interplanetary space. We developed a novel framework to study the storm-time variations in Van Allen Belts based on the distinct properties of large-solar wind drivers a using superposed epoch analysis with multiple reference times. The analysis revealed that CME-driven sheath regions effectively deplete the radiation belts at the geosynchronous orbit. The heliospheric database developed by our space physics team is the most comprehensive shock database. In August 2014 a PhD thesis on modeling of evolution of CME geometrical parameters and magnetospheric flux ropes was  defended.

    Solar superstorm

Figure 17: July 2012 solar superstorm captured by the twin STEREO spacecraft. (credit: NASA)