Some Turbulent Predictions for Parker Solar Probe

Abstract

From the the solar photosphere to the outer heliosphere, the Sun's plasma properties are fluctuating with a broad range of temporal and spatial scales. In fact, a turbulent cascade of energy from large to small scales is a frequently invoked explanation for heating the corona and accelerating the solar wind. NASA's Parker Solar Probe (PSP) is expected to revolutionize our understanding of coronal heating and magnetohydrodynamic (MHD) turbulence by performing in situ sampling closer to the Sun than any other prior space mission. This research note presents theoretical predictions for some properties of MHD turbulence (e.g., spacecraft-frame power spectra and variance anisotropies) in the regions to be explored by PSP. These results are derived from a previously published semi-empirical model of coupled Alfvenic and fast-mode turbulence in the fast solar wind. The primary reason for this research note is to show how straightforward it can be to extract useful predictions from existing theoretical models about measurable quantities that were not even considered when creating the models initially. The variance anisotropy, for example, may be an important quantity for distinguishing between different theoretical models for coronal heating and solar wind acceleration.