Solar Physics: The Polarimeter to UNify the Corona and Heliosphere (PUNCH) will image macroscopic features of the inner heliosphere and also admit sufficiently high spatial resolution to probe scales of turbulence within the upper end of the inertial range, close to the integral scale. Because PUNCH is an imager, the measurements it will make relate differently to the underlying turbulent environment of the outer corona and inner heliosphere than do more familiar in situ samples. We present a numerical study that combines magnetohydrodynamic simulations of turbulence together with forward-modeling synthesis of white- light data via the FORWARD code. We show that (i) the “usual” turbulence scalings are modified by the integration along the line of sight in an optically thin medium, and (ii) those scalings are still linked to the original properties of the turbulent field. This study is a first step in the process of analyzing and understanding the unprecedented information that PUNCH will provide.
(a) Density field snapshot in a 2D plane of the simulation ρ(x = 0, y, z), (b) 2D density obtained by integrating the 3D simulation domain in one direction ⟨ρ(x, y, z)⟩x, (c) normalized correlation functions obtained from these two fields. the red curve refers to ρ(x = 0, y, z), while the blue to ⟨ρ(x, y, z)⟩x. The horizontal line marks the 1/e level at which the correlation lengths are estimated (vertical lines). The averaging procedure dilutes the sharp gradients and the correlation length almost doubles from 1.9Rsun to 4.1Rsun. Notice that the density features in (a) can almost identically be observed in Fig. 5(c) because the NEAR FOV almost exactly matches the information on the TS with little to no stretching.