Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

DY: Fachverband Dynamik und Statistische Physik

DY 37: Fluid Dynamics and Turbulence

DY 37.4: Vortrag

Donnerstag, 3. April 2014, 15:45–16:00, ZEU 146

The solar wind as a turbulence laboratory- some new quantitative points of contact between theory and solar wind observations — •Sandra Chapman^1,2,3, Khurom Kiyani^4,1, Kareem Osman¹, Bogdan Hnat¹, and Ersilia Leonardis¹ — ¹CFSA, Physics, University of Warwick, UK — ²MPIPKS, Dresden, Germany — ³Mathematics and Statistics, UIT, Norway — ⁴Laboratoire de Physique des Plasmas, Ecole Polytechnique, Saclay, France

The solar wind flow has a Reynolds number of order 10^5. Single point sattelite observations of plasma parameters suitable for the study of turbulence are on timescales from below ion kinetic scales up to days. We will present methodology to quantify the scaling properties of turbulence from in-situ satellite observations in the solar wind that address the problems of scaling over a finite range and restricted sampling of rare extreme events.

Ideal fluid turbulence is characterized by non-Gaussian distributions of fluctuations which become progressively fat-tailed on smaller scales, and which exhibit a multifractal scale invariance, a behaviour also seen in the MHD inertial range of turbulence in the solar wind. We show that below the ion kinetic scales there is instead a cross-over to a quantitatively distinct global scale invariance and discuss the implications for the physics of kinetic range turbulence. Solar wind plasma turbulence is anisotropic due to the presence of a background field. We will discuss how this anisotropy also orders the scaling properties seen in solar wind turbulence.