Abstract
Abstract The Parker Solar Probe (PSP) routinely observes magnetic field deflections in the solar wind at distances less than 0.3 au from the Sun. These deflections are related to structures commonly called “switchbacks” (SBs), whose origins and characteristic properties are currently debated. Here, we use a database of visually selected SB intervals—and regions of solar wind plasma measured just before and after each SB—to examine plasma parameters, turbulent spectra from inertial to dissipation scales, and intermittency effects in these intervals. We find that many features, such as perpendicular stochastic heating rates and turbulence spectral slopes are fairly similar inside and outside of SBs. However, important kinetic properties, such as the characteristic break scale between the inertial to dissipation ranges differ inside and outside these intervals, as does the level of intermittency, which is notably enhanced inside SBs and in their close proximity, most likely due to magnetic field and velocity shears observed at the edges. We conclude that the plasma inside and outside of an SB, in most of the observed cases, belongs to the same stream, and that the evolution of these structures is most likely regulated by kinetic processes, which dominate small-scale structures at the SB edges.
Highlights
Parker Solar Probe (PSP) is the first mission to measure the inner heliosphere closer than 0.3 au from the Sun’s surface, with perihelion distances of ∼ 0.16 au during its first three encounters with the Sun
In order to understand the inertial slope behavior, we investigated possible relations of the fitted slope with multiple parameters, including plasma β, Velocity Distribution Function (VDF) moments, magnetic field and characteristics of its turbulent fluctuations, and radial distance
In this work, a comprehensive analysis of manually selected magnetic field SB events in PSP encounters 1 and 2 is performed in order to determine the characteristics of plasma inside and outside of the regions where the field is deflected
Summary
Parker Solar Probe (PSP) is the first mission to measure the inner heliosphere closer than 0.3 au from the Sun’s surface, with perihelion distances of ∼ 0.16 au during its first three encounters with the Sun. Results from previous missions had already motivated the community to invest significant effort into understanding the nature of SBs, though they were not observed nearly as frequently as by PSP. This interest has increased, as new data sets from PSP provide significantly larger populations of SBs and more detailed information on the associated plasma and electromagnetic field conditions due to increased measurement precision and cadence.
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