Higher-order Turbulence Statistics in the Sub-Alfvénic Solar Wind Observed by Parker Solar Probe

Zhang, J.; Huang, S. Y.; Yuan, Zhigang; Jiang, K.; Xu, S. B.; Bandyopadhyay, R.; Wei, Yong; Xiong, Qian; Wang, Z.; Yu, Lei; Lin, R. T.

doi:10.3847/1538-4357/ac8c34

Cited by 9 publications

(7 citation statements)

References 62 publications

(85 reference statements)

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“…The original flatness increases as the timescale τ decreases with a power-law dependence F ∼ τ −0.29 until τ = 0.5 s, which is close to the high-frequency break on the power spectra, an indicator of the boundary between the inertial range and the dissipation range. The flattening of the flatness below τ = 0.5 s is consistent with previous observations (Chhiber et al 2021;Zhang et al 2022). After setting the Figure 2.…”

Section: Resultssupporting

confidence: 92%

“…The intermittency in the solar wind turbulence is widely investigated by the nonlinear behavior of the scaling exponents of multiorder structure functions (e.g., Burlaga 1991;Horbury & Balogh 1997;Zhao et al 2020;Zhang et al 2022). The properties of intermittency in the near-Sun environment observed by Parker Solar Probe (PSP) revealed by the multiorder scaling exponents are frequently analyzed.…”

Section: Introductionmentioning

confidence: 99%

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Intermittency of Magnetic Discontinuities in the Near-Sun Solar Wind Turbulence

Huang

Wang

et al. 2023

ApJL

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The intermittency domain is in the magnetohydrodynamic inertial range but just above the dissipation range and contains the intermittent structures that influence the spectral index. However, the nature of these structures is still under debate and how they affect the higher-order scaling behavior in the near-Sun solar wind turbulence remains to be investigated. Here we use the magnetic field data measured by Parker Solar Probe in the near-Sun solar wind. We identify the intermittency by partial variance of increments method and conduct the multiorder structure functions analyses in the intermittency domain before and after removing the intermittency. We also perform for the first time the scaling analyses on the fluctuations of magnetic field direction given by the rotational angle θ = cos − 1 ( B 1 · B 2 ) / ∣ B 1 ∣ ∣ B 2 ∣ , in which B 1 and B 2 are the magnetic fields measured at two instants. We find that the multifractal scaling of the magnetic field could be predicted by the log-Poisson intermittency model with 2D sheetlike structures and a simple Kolmogorov −5/3 monoscaling recovers after the removal of the intermittency. We also find a similar behavior for the scalings of θ, suggesting that magnetic discontinuities are involved in the energy transfer process of solar wind turbulence.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Intermittency of Magnetic Discontinuities in the Near-Sun Solar Wind Turbulence

Huang

Wang

et al. 2023

ApJL

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“…However, observations of the sub-Alfvénic wind had been limited until the Parker Solar Probe (PSP) mission, which aims to explore the solar wind source region (Fox et al 2016), sampled the sub-Alfvénic wind for the first time during its eighth solar encounter (Kasper et al 2021). Studies have been performed on this first sampling as well as a few subsequent intervals of the sub-Alfvénic wind to determine the properties of the coronal plasma (e.g., Alberti et al 2022;Bandyopadhyay et al 2022;Zank et al 2022;Zhang et al 2022;Zhao et al 2022). Now, with a broader data range available, extensive sub-Alfvénic intervals can be identified from the PSP measurements from encounter 8 to the more recent encounter 14.…”

Section: Introductionmentioning

confidence: 99%

Properties of Steady Sub-Alfvénic Solar Wind in Comparison with Super-Alfvénic Wind from Parker Solar Probe Measurements

Jiao,

Liu,

Ran

et al. 2023

ApJ

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We identify more than 10 steady sub-Alfvénic solar wind intervals from the measurements of the Parker Solar Probe (PSP) from encounter 8 to encounter 14. An analysis of these sub-Alfvénic intervals reveals similar properties and similar origins. In situ measurements show that these intervals feature a decreased radial Alfvén Mach number resulting from a reduced density and a relatively low velocity, and that switchbacks are suppressed in these intervals. Magnetic source tracing indicates that these sub-Alfvénic streams generally originate from the boundaries inside coronal holes or narrow/small regions of open magnetic fields. Such properties and origins suggest that these streams are mostly low Mach-number boundary layers (LMBLs), which is a special component of the pristine solar wind proposed by Liu et al. We find that the LMBL wind, the fast wind from deep inside coronal holes, and the slow streamer wind constitute three typical components of the young solar wind near the Sun. In these sub-Alfvénic intervals, the Alfvén radius varies between 15 and 25 solar radii, in contrast with a typical 12 radii for the Alfvén radius of the super-Alfvénic wind. These results give a self-consistent picture interpreting the PSP measurements in the vicinity of the Sun.

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“…Solar wind turbulence plays an important role in the energy transfer process in the heliosphere, as it provides a channel for the energy cascade from large scale to small scale. The turbulent fluctuations of the magnetic field in the solar wind display a probability distribution function deviating from the Gaussian distribution with a long tail, which indicates the existence of the intermittency (Bruno & Carbone 2013;Zhang et al 2022). An effective way to identify the intermittency is the partial variance of increments (PVI) method (Greco et al 2008), which measures the large amplitude of fluctuations.…”

Section: Introductionmentioning

confidence: 97%

Influence of Intermittency on the Energy Transfer Rate of Solar Wind Turbulence

Wu,

Huang,

Wang

et al. 2023

ApJL

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The intermittency in the solar wind turbulence manifests itself in the anisotropic scaling due to the anisotropic spectral index and the intermittent level based on the extended P model. However, the influence of intermittency on the energy transfer rate remains unclear. Here we apply the partial variance of increments method to identify the intermittency for the magnetic field measurements in the fast solar wind from the Ulysses spacecraft. We distinguish the sampling direction using the angle θ RB between the local magnetic field and radial direction to study the anisotropy. We perform the multiorder structure function analyses and adopt the log-Poisson cascade model to describe the role of intermittency in the cascade process. We find that the anisotropy of the scaling becomes isotropic with a complete removal of intermittency. We compare explicitly the anisotropy of the energy transfer rate before and after removing the intermittency for the same interval for the first time. We find a distinct anisotropy with a cascade enhancement in the direction perpendicular to the local magnetic field. The removal of the intermittency greatly weakens the anisotropy by mainly reducing the perpendicular energy transfer rate. Our findings suggest that the intermittency effectively enhances the energy transfer rate, in particular in the perpendicular direction in the solar wind turbulence.

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Higher-order Turbulence Statistics in the Sub-Alfvénic Solar Wind Observed by Parker Solar Probe

Cited by 9 publications

References 62 publications

Intermittency of Magnetic Discontinuities in the Near-Sun Solar Wind Turbulence

Intermittency of Magnetic Discontinuities in the Near-Sun Solar Wind Turbulence

Properties of Steady Sub-Alfvénic Solar Wind in Comparison with Super-Alfvénic Wind from Parker Solar Probe Measurements

Influence of Intermittency on the Energy Transfer Rate of Solar Wind Turbulence

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