The Correlation Function for Magnetic Field Fluctuations at Ion Dissipation Scales in the Solar Wind
Year: 2025
Type: article
Abstract: This study investigates energy dissipation in small‐scale solar wind turbulence using a novel approach to autocorrelation function analysis leveraging high‐resolution data from the Magnetospheric Multiscale Mission (MMS). We analyze magnetic field fluctuations at ion dissipation scales, focusing on short 20‐s intervals to isolate dissipation‐scale dynamics. Using MMS's fluxgate magnetometer, fast plasma investigation, and energetic particle detector, we compute normalized correlation functions as functions of the interplanetary magnetic field cone angle. Our results show that turbulence is correlated over short spatial scales (100–1,000 km), with shorter correlation lengths in the compressional component compared to the transverse components. We find that the transverse correlation lengths differ most when the interplanetary magnetic field is nearly perpendicular to the solar wind flow (cone angle ), and that they vary approximately as the inverse sine of the cone angle. The characteristics of the correlation length suggest that the turbulence observed is primarily two‐dimensional. These findings highlight the anisotropic nature of dissipation‐scale turbulence and its dependence on solar wind conditions, providing insights into energy transfer in space plasmas.
DOI: 10.1029/2025ja034569
Institutions: University of New Hampshire, Johns Hopkins University, Johns Hopkins University Applied Physics Laboratory, Los Alamos National Laboratory, The Aerospace Corporation, Goddard Space Flight Center, Austrian Academy of Sciences, University of California, Los Angeles, Southwest Research Institute
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,070
Awards: G2750416160, G7087141888
OpenAlex ID: W4417448703