Space physics

The key research foci of the University of Helsinki (UH) space physics team are the evolution and propagation of coronal mass ejections (CMEs) from Sun to Earth, interaction of the solar wind and solar eruptions with the near-Earth space environment, and interplanetary shock waves. We develop numerical simulations, empirical models and analyze observations from several ESA and NASA spacecraft. Solar wind-magnetosphere coupling is studied within a joint Academy of Finland Consortium with the School of Electrical Engineering of Aalto University. Our team is also part of the FP7 HELCATS project (led by Rutherford  Appleton Laboratory, UK), which focuses on heliospheric imaging of CMEs and the connection between CME properties in remote sensing and in-situ observations. High-lights of 2014 have been the official launch of the Comprehensive Heliospheric Shock Database (ipshocks.fi), fully developed and maintained by the UH space physics team), analysis of Van Allen radiation belts and the progress done with modelling the solar corona and the solar wind.

Our Heliopsheric Shock Database is the most comprehensive interplanetary shock database. It features fast collisions shocks from a number of key present and past space missions and has straightforward search tools and data download options.  The main development of coronal simulations is done within the University of Helsinki Three-Year Grant Project. The project aims at developing fully data-driven coupled coronal simulations using precious vector magnetograms from Solar Dynamic Observatory. This approach enables analysing magnetic fields in erupting CMEs, a key missing element in understanding CME initiation and evolution and improving long-lead-time space weather forecasting. The UH space physics team is also the lead developer of Euhforia, a recently launched novel physics-based inner-heliosphere  model. The model can provide forecasts of the plasma conditions up to seven days in advance, and is currently transitioning to daily forecasting operations in order to help in mitigating the effects of space weather on European technological assets. The team has also developed a prototype of a novel 3-D CME  a model CMEs, which takes into account all major geometrical deformation a CME experiences during its propagation. Our novel framework to analyse storm-time variations in Van Allen Belts based on the characteristics of large-solar wind drivers was published in Geophysical Research Letters. We have continued to analyse radiation belt response using the energy and distance resolved observations from the Van Allen Probes.

    Solar superstorm

Radial speed of the solar wind in the ecliptic plane (top left) and a meridional plane including Earth (top right) given by the inner heliosphere model Euhforia developed mainly at UH. During June 20-30, 2015 several coronal mass ejections were released from the Sun on an Earthward trajectory. The model is able to accurately capture the dynamics of these events as seen in the lower panel that compares the simulation results (blue) with in-situ spacecraft observations (red).