Clustering of Intermittent Magnetic and Flow Structures near Parker Solar Probe's First Perihelion - A Partial-variance-of-increments Analysis

Rohit ChhiberM. L. GoldsteinB. A. MarucaA. ChasapisW. H. MatthaeusD. RuffoloR. BandyopadhyayT. N. ParasharR. QudsiT. Dudok De WitS. D. BaleJ. W. BonnellK. GoetzP. R. HarveyR. J. MacDowallD. MalaspinaM. PulupaJ. C. KasperK. E. KorreckA. W. CaseM. StevensP. WhittleseyD. LarsonR. LiviM. VelliN. RaouafiUniversite d'OrleansUniversity of Minnesota Twin CitiesSpace Sciences Laboratory at UC BerkeleyUniversity of California, Los AngelesUniversity of Michigan, Ann ArborUniversity of California, BerkeleyUniversity of Maryland, Baltimore CountyUniversity of DelawareJohns Hopkins University Applied Physics LaboratoryImperial College LondonMahidol UniversitySmithsonian Astrophysical ObservatoryNASA Goddard Space Flight CenterThe Bartol Research InstituteUniversity of Colorado Boulder2020-08-252020-08-252020-02-01Astrophysical Journal, Supplement Series. Vol.246, No.2 (2020)006700492-s2.0-85081672183https://repository.li.mahidol.ac.th/handle/20.500.14594/57864© 2020. The American Astronomical Society. All rights reserved.. During the Parker Solar Probe's (PSP) first perihelion pass, the spacecraft reached within a heliocentric distance of ∼37 R o&dot; 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's 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.Mahidol UniversityEarth and Planetary SciencesPhysics and AstronomyClustering of Intermittent Magnetic and Flow Structures near Parker Solar Probe's First Perihelion - A Partial-variance-of-increments AnalysisArticleSCOPUS10.3847/1538-4365/ab53d2