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Dissipative structures and kinetic processes in the near Earth plasmas

Final Report Summary - GEOPLASMAS (Dissipative structures and kinetic processes in the near Earth plasmas)

The Geoplasmas project had to objective to study the phenomena and instabilities which occur in the Earth's plasma environment, and in particular the processes of energy transfer, energy dissipation, and particle acceleration which occur in the kinetic plasma regimes. The geospace environment is composed by ionized gases, or plasmas, of varying density, temperatures, and dynamic motions. These plasmas originate partly from the high altitude layers of the Earth’s atmosphere, and partly from the flow of solar wind plasma coming from the hot solar corona. Understanding the interaction, heating, transport, and acceleration processes of these plasmas is one of the main objectives of space plasma physics and of solar terrestrial physics.

The Geoplasmas exchange programme involved a consortium of five research institutions – the University of Calabria (coordinator, Italy) (Unical), the Österreichische Akademie der Wissenshaften - Institute fuer Weltraumforschung (Austria) (OeAW - IWF), the Space Research Institute of the Russian Academy of Sciences (Russia) (IKI), the Tbilisi University (Georgia) (Tbilisi Univ), and the Saint Petersburg University (Russia) (SPBU) – which have a long research experience in various fields of space plasma physics. The programme lasted 36 months, with start on April 2011 and end on March 2014. Durign this period, 33 person-months of secondments among the participating institution have been carried out. The intense collaboration between the participants has led to the publication of more than 35 scientific papers on primary international journals, and more than 50 presentations at international conferences, mostly in Europe.

The specific objectives of this exchange programme were to investigate the dissipation processes in the magnetospheric and ionospheric environment like magnetic reconnection, turbulent heating and acceleration, turbulent transport, and the influence of shear flows on the development of turbulence, as described in the four work packages: WP1. Magnetic reconnection; WP2. Turbulent acceleration; WP3. Shear flows; WP4. Plasma transport and acceleration in planetary magnetospheres.
All workpackages have been carried out, and some new fields of research have been started, like the study of the wave-particle interaction in the field of two waves in a magnetized plasma, the study of the relation between acceleration due to reconnection jets in the Earth's magnetotail and in the solar corona, and the turbulent acceleration of ions heavier than protons in the Earth's magnetotail.

A number of important scientific results have been reached and published on primary scientific journals. Highlights include: (1) the study of particle acceleration in the Earth's magnetotail by means of spatially intermittent fluctuations and by 3D moving plasmoids, with results which compare well with spacecraft observations (Unical, IKI). (2) The finding of two different types of electric current sheets in the Earth's magnetopause, obtained by analyzing Cluster spacecraft data (OeAW-IWF, IKI). (3) The discovery of plasma flow bouncing in association with oscillatory flow braking and flow burst entropy control of its final destination distance in the magnetotail (OeAW-IWF, SPBU). (4) The use of simultaneous observations of four THEMIS spacecraft distributed along the magnetotail to investigate the electron heating in the magnetotail current sheet; this investigation has revealed the dominance of the adiabatic mechanisms for electron energization (IKI, OeAW-IWF). (5) The investigation of the role of nonlinear magnetic waves produced by transient reconnection for heavy ion acceleration in solar corona; it is shown that these waves can effectively accelerate heavy ions via resonant and nonresonnat regimes of interactions; this mechanism of acceleration is more effective for ions with a larger mass and/or with a larger electric charge, and is very promising for explaining the preferential heating of heavy ions in the solar corona (IKI, Unical). (6) A further novelty is the observation of a magnetohydrodynamics vortex chain in the Earth's magnetotail, based on data of the THEMIS spacecraft, and their comparison with the results of MHD numerical simulations (Unical, Tbilisi Univ, OeAW-IWF).

In conclusion, the Geoplasmas project was extremely successful from both the point of view of scientific results and of enhanced collaboration among participants, with some future activities already planned.

The project results are very important for science policy makers. Indeed, the Earth's magnetosphere and the particles therein accelerated are one of the main threats for Earth-orbiting spacecraft, and the project results allow to improve the existing models for space weather predictions. Also, the detailed understanding of physical phenomena in the Earth's magnetosphere, attained thanks to the in situ exploration by spacecraft, can be used to gain insights into other astrophysical plasmas which can be studied only remotely.

From the point of view of civil society and European Union, the Geoplasmas project has allowed to strengthen the research collaboration between the members of the participating institutions, thanks to the many exchange visits. An important result of the project is the establishment of collaborative activities among young researchers from IKI, OeAW-IWF, Unical, SPBU, and Tbilisi Univ. This ensures for a continuation of the collaboration among the involved institutions. Gender aspects were taken well into account, since eight female researchers were actively involved in the project and in the exchange visits.

Contact person: Gaetano Zimbardo, Scientific Responsible, University of Calabria, Italy.