Large Amplitude Switchback Turbulence: Possible Magnetic Velocity Alignment Structures
Switchbacks are widely acknowledged phenomena observed by the Parker Solar Probe and appear to occur in patches. Previous studies focused on the fluctuations at the magnetic reversals. However, the nature of the fluctuations inside the switchbacks remains unknown. Here we utilize the magnetic field data and plasma data measured by the Parker Solar Probe in the first four encounters. We investigate the fluctuations in the switchback intervals of 100 s with $B_R 0$ at every instant and compare them to the fluctuations in the nonswitchback intervals of 100 s with $\theta _\mathrmRB 160^\circ $ at every instant. We calculate normalized cross-helicity $\sigma _\rmc$ , normalized residual energy $\sigma _\rmr$ , correlation coefficient C<SUB>vb</SUB> between $\boldsymbol\delta \boldsymbolv_\rmA$ and $\boldsymbol\delta \boldsymbolv$ , Alfvén ratio r<SUB>A</SUB>, and the amplitude of magnetic and kinetic fluctuations. We find that the switchback intervals exhibit a distribution of $\sigma _\rmc$ similar with the nonswitchback intervals. However, the r<SUB>A</SUB> of switchback intervals is around 0.35, while the nonswitchback intervals have r<SUB>A</SUB> around 0.65, indicating the fluctuations in the switchbacks are more magnetically dominated. We also find that the distribution pattern of pixel average amplitude of both $\boldsymbol\delta \boldsymbolv_\rmA$ and $\boldsymbol\delta \boldsymbolv$ of switchback intervals in the C<SUB>vb</SUB>- $\sigma _\rmr$ plane show a vertical stripe feature at $C_\mathrmvb 0.8$ , illustrating the possible magnetically dominant magnetic-velocity alignment structure. These results will help us to understand the nature and the formation of the switchback turbulence.
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The Astrophysical Journal
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