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Abstract:
We use state of the art in-situ data recorded by two space missions, ESA’s CLUSTER and NASA’s MMS, to test the effect of the quasi-parallel versus quasi-perpendicular bow-shock geometry on the properties of turbulence in the magnetosheath. We construct and analyze a database of simultaneous crossings of Earth’s magnetosheath by Cluster and MMS during 2017-2019. The dawn/dusk flank is more often associated to a quasi-parallel/quasi-perpendicular shock.Using a limited dataset, we found a correlation between the bow shock characteristics and the properties of turbulence behind the shock - Earth’s magnetosheath (Teodorescu et al. 2021, https://doi.org/10.3847/1538-4357/abe12d). In this analysis, two quasi-perpendicular magnetosheath crossings depict different scenarios:i) data recorded during one of Cluster’s magnetosheath crossing indicate three different power- law scaling regimes (injection, inertial, and kinetic) separated by two spectral breaks, consistent with the scenario of fully developed turbulence.ii) data from a second Cluster magnetosheath crossing indicate only two power-law scaling regimes: a spectral slope shallower than the Kolmogorovian solar wind power-law index is determined at magnetohydrodynamic scales, spanning more than three frequency decades, which is separated by a spectral break from the kinetic regime. We suggest that this behavior might be controlled by the structure of the bow shock; solar wind turbulent fluctuations are only partially destroyed while they are carried across the bow shock.
