Observations of Near-Sun Turbulent Density Fluctuations with the Wide Field Imager for Solar Probe Plus (WISPR)

Abstract:

The trajectory of Solar Probe Plus (SPP) as it transits through the solar corona with a perihelion of < 10 Rs will allow much higher contrast observations of small-scale density fluctuations with higher cadence than is possible from 1 AU. The WISPR instrument will implement a high-cadence mode (up to 1 second) in which it will obtain images of the corona and inner heliosphere with high spatial resolution over a restricted field of view around specified regions of interest. Two-dimensional power spectra of the density fluctuations can then be constructed with variable cadences for direct comparison to similar spectra obtained by in-situ instruments on SPP and Solar Orbiter (SO). WISPR will provide density power spectra at or below the spectral break between inertial and injection scales, even at the closest perihelion approach, for different coronal structures. When combined with tomographic information from synoptic images, the WISPR turbulence program will be a major enhancement to the turbulence measurements from the SPP and SO in-situ instruments resulting in a much more robust understanding of the near-Sun turbulence. We will present details of the planned observations and will discuss the coordinated science objectives that can be addressed using these observations.