Solar wind structures – correlation between OMNI and THEMIS data

Small-scale solar wind structures, consistently impacting Earth, provide a fundamental energy transfer from the Sun to the Geospace. However, what we measure at L1 might not be consistent with structures arriving at Earth. We explore how well OMNI data resemble direct near-Earth measurements using THEMIS. We focus on variations in large-scale solar wind structures such as coronal mass ejections (CMEs) and stream interaction regions (SIR) with their distinct substructures. Our study is based on existing CME/SIR lists of events defined by Koller et al. [2022] in OMNI data. For the given time ranges, we compare the timing and appearance of the structures in the solar wind plasma and magnetic field parameters as probed by OMNI and THEMIS. We find that, on average, correlations between the structures measured at OMNI and THEMIS increase with the length of the measured structure. In addition, we find shifts between the structure measurements of a few minutes. Moreover, for CMEs that could form a sheath, we found an above-average coverage in the THEMIS measurements. By providing a more comprehensive understanding of solar wind dynamics and the relationships between their substructures measured at different locations, this research will significantly contribute to the field of space weather and heliospheric physics.