Turbulence Transport in Sub-Alfvenic and Subsonic Astrophysical Plasma Flows

• Applicant: Privatdozent Dr. Horst Fichtner
• Subject Area: Astrophysics and Astronomy
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 390744075

With the proposed 3-year research project we intend to intensify the successful collaboration between the Ruhr-Universität of Bochum, Germany, and the University of Waikato, Hamilton, New Zealand, that was recently initiated within the framework of a dedicated 1-year DFG funding on the topic of coupled plasma fluid and turbulence transport modelling of the heliosphere and of astrospheres. The main goals of the proposed research project are (i) a quantitative assessment of the transport of turbulence in the outer sub-Alfvenic and subsonic regimes of the solar wind and other stellar winds, and (ii) a quantitative study of the resulting transport of energetic particles. Consequently, the primary objective of the project is the answering of the following three scientific key questions regarding the turbulence evolution as well as the transport processes and the corresponding transport equation:(1) How can the transport of turbulence in the partially sub-Alfvenic and subsonic inner heliosheath (between the solar wind termination shock and the heliopause) and in stellar astrosheaths (between the stellar wind termination shocks and the bow shocks) be described quantitatively within the framework of a multi-component model?,(2) How does the turbulence evolution in the inner heliosheath and in stellar astrosheaths influence the spatial and temporal variation of the transport parameters of cosmic rays?, and (3) What are the solutions of the cosmic ray transport equation when using the new compressible turbulence model to obtain the transport parameters?By attaining the goals of this timely project we will not only supplement the much needed models of turbulence evolution with a new, three-component description that, for the first time, will allow for a simultaneous and self-consistent treatment of quasi-twodimensional, wave-like, as well as compressive fluctuations, but we will also establish a significantly improved conceptual framework for the modelling of the transport conditions of energetic particles in both the inner heliosheath and in stellar astrosheaths. In view of the recent, and ongoing, in-situ measurements made in the heliosheath by the Voyager spacecraft and the potential importance of astrospheres for cosmic ray acceleration and cosmic ray anisotropies, both transport environments are of high contemporary interest for the helio- and astrophysics communities.

• DFG Programme: Research Grants
• International Connection: New Zealand
• Cooperation Partner: Professor Dr. Sean Oughton