Clustering of Intermittent Magnetic and Flow Structures near <i>Parker Solar Probe</i> \textquoterights First Perihelion\textemdashA Partial-variance-of-increments Analysis

Author
Keywords
Abstract
<p>During the Parker Solar Probe\textquoterights (PSP) first perihelion pass, the spacecraft reached within a heliocentric distance of ̃37 R<sub>☉</sub> and observed numerous magnetic and flow structures characterized by sharp gradients. To better understand these intermittent structures in the young solar wind, an important property to examine is their degree of correlation in time and space. To this end, we use the well-tested partial variance of increments (PVI) technique to identify intermittent events in FIELDS and SWEAP observations of magnetic and proton-velocity fields (respectively) during PSP\textquoterights first solar encounter, when the spacecraft was within 0.25 au from the Sun. We then examine distributions of waiting times (WT) between events with varying separation and PVI thresholds. We find power-law distributions for WT shorter than a characteristic scale comparable to the correlation time of the fluctuations, suggesting a high degree of correlation that may originate in a clustering process. WT longer than this characteristic time are better described by an exponential, suggesting a random memory-less Poisson process at play. These findings are consistent with near-Earth observations of solar wind turbulence. The present study complements the one by Dudok de Wit et al., which focuses on WT between observed "switchbacks" in the radial magnetic field.</p>
Year of Publication
2020
Journal
The Astrophysical Journal Supplement Series
Volume
246
Number of Pages
31
Date Published
02/2020
URL
https://iopscience.iop.org/article/10.3847/1538-4365/ab53d2
DOI
10.3847/1538-4365/ab53d2