On the Identification of Coherent Structures in Space Plasmas: the Magnetic Helicity-PVI Method

Abstract

Plasma turbulence can be viewed as a magnetic landscape populated by large and small scale coherent structures. In this complex network, large helical magnetic tubes might be separated by small scale magnetic reconnection events (current sheets). However, the identification of these magnetic structures in a continuous stream of data has always been a challenging task. Here we present a method that is able to characterize both the large and small scale structures of the turbulent solar wind, based on the combined use of a filtered magnetic helicity ($H_m$) and the Partial Variance of Increments (PVI). This simple, single-spacecraft technique, has been validated first via direct numerical simulations of plasma turbulence and then applied to data from the Parker Solar Probe (PSP) mission. This novel analysis, combining $H_m$&PVI methods, reveals that a large number of flux tubes populate the solar wind and continuously merge in contact regions where magnetic reconnection and particle acceleration may occur.

References in corpus (11)

• The Solar Orbiter mission -- Science overview
• Magnetic Reconnection and Intermittent Turbulence in the Solar Wind
• Observation-based modelling of magnetised Coronal Mass Ejections with EUHFORIA
• Identification of Magnetic Flux Ropes from Parker Solar Probe Observations during the First Encounter
• Automated detection of small-scale magnetic flux ropes in the solar wind: First results from the Wind spacecraft measurements
• Clustering of Intermittent Magnetic and Flow Structures near Parker Solar Probe's First Perihelion -- A Partial-Variance-of-Increments Analysis
• Exploring the Statistics of Magnetic Reconnection X-points in Kinetic Particle-in-Cell (PIC) Turbulence
• Kinetic Alfvén waves generation by large-scale phase-mixing
• Small-scale Magnetic Flux Ropes in the First two Parker Solar Probe Encounters
• Ion Diffusion and Acceleration in Plasma Turbulence
• Statistical analysis of ions in two-dimensional plasma turbulence

Cited by in corpus (9)

• Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
• On the transmission of turbulent structures across the Earth's Bow Shock
• Magnetic field intermittency in the solar wind: PSP and SolO observations ranging from the Alfven region out to 1 AU
• Parker Solar Probe Observations of Helical Structures as Boundaries for Energetic Particles
• The S-Web Origin of Composition Enhancement in the Slow-to-Moderate Speed Solar Wind
• Automated identification of current sheets -- a new tool to study turbulence and intermittency in the solar wind
• Relaxation of the turbulent magnetosheath
• Evaluation of scale-dependent kurtosis with HelioSwarm
• Small-scale magnetic flux ropes and their properties based on in-situ measurements from Parker Solar Probe