Bremen 2017 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 7: Sonne und Heliosphäre II
EP 7.3: Vortrag
Mittwoch, 15. März 2017, 09:15–09:30, GW2 B2880
A generalized two-component model of solar wind turbulence — •Horst Fichtner1, Tobias Wiengarten1, Sean Oughton2, Eugene Engelbrecht3, Jens Kleimann1, and Klaus Scherer1 — 1Ruhr-Universitaet Bochum, Institut fuer Theoretische Physik IV — 2University of Waikato, Hamilton, New Zealand — 3Space Research Centre, North-West University, Potchefstroom, South Africa
We extend a two-component model for the evolution of fluctuations in the solar wind plasma so that it is fully three-dimensional and also coupled self-consistently to the large-scale magnetohydrodynamic equations describing the background solar wind. The two classes of fluctuations considered are a high-frequency parallel propagating wave-like piece and a low-frequency quasi-two-dimensional component. For both components, the nonlinear dynamics is dominated by quasi-perpendicular spectral cascades of energy. Driving of the fluctuations by, for example, velocity shear and pickup ions is included. Numerical solutions to the new model are obtained using the CRONOS framework, and validated against previous simpler models. Comparing results from the new model with spacecraft measurements, we find improved agreement relative to earlier models that employ prescribed background solar wind fields. Finally, the new results for the wave-like and quasi-twodimensional fluctuations are used to calculate ab initio diffusion mean-free paths and drift lengthscales for the transport of cosmic rays in the turbulent solar wind.