Bremen 2017 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 7: Sonne und Heliosphäre II
EP 7.5: Vortrag
Mittwoch, 15. März 2017, 09:45–10:00, GW2 B2880
Model for Reduced Power Spectra of Critically Balanced Solar Wind Turbulence with Damping by Kinetic Alfvén Waves — •Anne Schreiner1, Joachim Saur1, Michael von Papen1, Olga Alexandrova2, and Catherine Lacombe2 — 1Universität zu Köln, Institut für Geophysik und Meteorologie — 2Paris Observatory Meudon
The observed spectral structure of magnetic turbulence at electrons scales in the solar wind is still not sufficiently understood. Analytical dissipation models for solar wind turbulence are usually derived in the three-dimensional wavenumber space. However, in-situ observations of magnetic fluctuations are obtained in a one-dimensional reduced form in the spacecraft frame, where various wavevectors contribute to the spectral energy density at a certain frequency. Based on a forward modeling approach by von Papen & Saur (2015), we calculate reduced spectral energy densities from a three-dimensional energy distribution in wavenumber space under the assumption of critically balanced turbulence and damping via wave-particle interactions of kinetic Alfvén waves. The damping is described through the imaginary part of the kinetic Alfvén wave frequency, which we obtain from linear Vlasov theory. We compare the spectral energy densities to a set of observations obtained from one-dimensional magnetic field measurements of the Cluster spacecraft analyzed in Alexandrova et al. (2012).