Multiscale Solar Wind Turbulence Properties inside and near Switchbacks measured by Parker Solar Probe

Abstract

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 a 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.

Small-scale Magnetic Flux Ropes with Field-aligned Flows via the PSP In-situ Observations

“…Namely, the distributions of duration, scale size, average solar wind speed, and FR/FRFF magnetic fields versus radial distances r, are shown. Moreover, we compare the FR/FRFF events with the switchback spikes in Kasper et al (2019); Martinovic et al (2021). Three cases are selected and displayed with their time-series plots, cross-section maps, and the P t versus A curves, derived from the GS-type reconstruction.…”

“…These two cases possess relatively modest Alfvénicity. The corresponding spikes are reported in Kasper et al (2019) and included in a recently extended list (Martinovic et al 2021).…”

“…Given the increased sample size of events from E1 to E5, especially by including FRFFs which share the same property of being Alfvénic with switchbacks, we compare the FRFFs and FRs with the velocity spikes in lists of switchbacks (Kasper et al 2019;Martinovic et al 2021). The identification of switchbacks in their study requires an occurrence of a clear rotation of the magnetic field by more than 45 • for over 10 s with respect to the quiet solar wind background and returning to the normal condition.…”