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Quantifying Energy Circulation in Space Plasma

Final Report Summary - QUESPACE (Quantifying Energy Circulation in Space Plasma)

The QuESpace project aims to quantify energy circulation in space plasmas. Scientifically, energy transfer is a fundamental plasma physical problem having many applications in a variety of plasma environments ranging from coronal heating on the Sun to electric heating in the ionosphere, which is the main uncertainty in the re-entry of spacecraft to the ground. Technologically, understanding the plasma and energy transport properties is a step toward predictions of the space environment needed for spacecraft design and operations. Plasma phenomena within the near-Earth space create space weather – the harmful effects caused by enhanced solar radiation or dynamical processes that can endanger technological systems or human life in space. Aviation, HF radio signals and GPS positioning are affected by accelerated energetic particles in the polar ionosphere. Accurate characterization of the physics of space weather needs to be based on the accurate description of the system’s energy balance. Prior to QuESpace, the space physics community still lacked an accurate and self-consistent numerical model capable of describing the global plasma system.
QuESpace work was divided into observational and modeling themes. Observationally, the previous state-of-the-art was based on empirical proxies or single event studies. Up to now, there are no observational studies on the global energy transfer through the outer layer of the Earth’s magnetic field domain (the magnetopause) because it would require a large amount of spacecraft and a method by which energy can be measured. We carried out the first global energy conversion investigation at the magnetopause using a large statistical database constructed from the European Space Agency’s Cluster spacecraft measurements. This effort is an important step towards quantifying the global energy balance needed in accurate space weather forecasts. With these estimates, the magnitudes of events in the space weather modeling frameworks may be adjusted to match observational evidence.
While space missions provide critical experimental information on the Solar-Terrestrial system, they can only make local measurements in a spatially limited volume. To obtain a holistic picture of the near-Earth space environment, state-of-the-art simulations utilizing the full power of modern experiments are needed. Vlasiator (http://vlasiator.fmi.fi) is a new global kinetic scale space environment simulation developed in QuESpace, defining a new state-of-the-art in space plasma physics simulations.
At the start of QuESpace, developing a global kinetic scale space environment model was deemed impossible due to the massive computations they would require. Vlasiator combines the hybrid-Vlasov theory with top-tier high performance computing. We employed the most novel computational methods in parallelization, and developed completely new innovations to achieve the dream of describing the global space environment accurately on ion scales. In 2012, we got a prestigious supercomputing grant from the Partnership for Advanced Computing in Europe (PRACE), enabling the world’s first global hybrid-Vlasov runs in 2013, utilizing the Hermit supercomputer in Stuttgart. Vlasiator models the near-Earth space in unprecedented detail on ion scales, producing noise-free distribution functions comparable to those obtained by spacecraft. In contrast to the spacecraft observations, Vlasiator models the nonlinear global case in a holistic manner where processes may be followed in space and time, providing a major step forward. The first results show that Vlasiator provides a revolutionary way of explaining processes with realistic cause-and-effect relationships. Vlasiator is the world’s new benchmark in global space plasma simulations, realized through the ERC Starting grant 200141-QuESpace.