Observations of Plasma Turbulence and Heating from the Solar Wind and Simulations

Abstract:

The cascade of energy by plasma turbulence has been shown to occur in, and heat, the solar wind. Recent work in the study of solar wind turbulence has focussed, in the most part, on advanced data analysis techniques, such as third moment structure functions, wavelets, conditional data sampling, multi-spacecraft observations and reconstruction of 2D k-spectra with tomography, and statistical studies from long time series of spacecraft observations. These techniques are complex and contain different assumptions about the qualities of the data underpinning the measurements. Here, we will review recent advances and discoveries in the study of plasma turbulence from solar wind data analysis and discuss how benchmarking of techniques against one another could be pursued and how simulations can be used to aid in the understanding of the results of solar wind data analysis, in particular in the framework of the “Turbulence Dissipation Challenge” (Parashar et al., Journal of Plasma Physics, Volume 81, Issue 05, 905810513, 2015). We will pay particular attention to observing two different heating mechanisms: stochastic heating and resonant wave-particle interactions. The magnetic helicity of the solar wind is shown to separate into two distinct components, one originating from pseudo-Alfvenic (k may have a component parallel to the magnetic field) and one from the Alfvenic fluctuations (k is strictly perpendicular). The solar wind results are compared with “pseudo-spacecraft” data from large 3D PIC simulations.