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## Overview Parker Solar Probe, NASA's mission to study the Sun's corona, made a notable observation near its 23rd perihelion in March 2025, sampling an extended interval of sub-Alfvénic solar wind likely originating from a large equatorial coronal hole (arXiv:2609.26720, September 23, 2026). At heliocentric distances of approximately 10 solar radii, with speeds mostly above 400 km/s, researchers characterized this as a first example of 'polar coronal hole-like (PCH-l) fast' solar wind observed in the sub-Alfvénic solar corona. Separately, researchers using Parker Solar Probe measurements spanning 0.1-0.8 au reported a robust 'bihelical' structure in magnetic helicity emerging at the magnetohydrodynamic (MHD)-kinetic interface in the solar wind (arXiv:2507.13213, October 14, 2026). Magnetic helicity is typically indistinguishable from noise in the solar wind inertial range, making this structured pair of positive and negative spectral peaks notable (arXiv:2507.13213). A third study examined turbulence in velocity space rather than physical space, analyzing the Hermite spectrum of ion velocity distribution functions (VDFs) measured by Parker Solar Probe in a superalfvénic stream in the inner heliosphere, reporting first insights into a velocity-space turbulent cascade near the Sun (arXiv:2512.01492, October 23, 2026). ## Scientific Significance The sub-Alfvénic corona is a region where the solar wind speed is slower than the local Alfvén speed—a regime Parker Solar Probe was specifically designed to reach and study. The observation is notable because it represents fast wind with polar coronal hole-like characteristics found in an unexpected location—well inside the nominal boundary typically associated with such fast wind—raising questions about solar wind origin and acceleration mechanisms (arXiv:2609.26720). Researchers used the data to characterize turbulence properties of this unique interval. The newly reported bihelical magnetic helicity structure exhibits systematic spectral migration toward lower frequencies with increasing heliocentric distance, and this evolution deviates from local kinetic scaling laws, such as the radial decline of the ion cyclotron frequency (arXiv:2507.13213, October 14, 2026). This suggests nonlocal physics govern the transition between MHD and kinetic turbulence regimes in the solar wind, an area of active study using Parker Solar Probe data. The Hermite decomposition study extends turbulence analysis beyond physical-space quantities (like magnetic field or velocity fluctuations) into velocity space itself, examining how collisionless plasma processes generate fine structure in ion VDFs. Prior work using this technique had focused on magnetosheath data and numerical simulations; this represents an initial application to near-Sun solar wind data from Parker Solar Probe, in a superalfvénic (rather than sub-Alfvénic) stream (arXiv:2512.01492, October 23, 2026). ## Strategic Importance Understanding solar wind turbulence and its origins has implications for space weather forecasting, which affects satellite operations, power grids, and communications infrastructure. Parker Solar Probe continues to be a primary source of novel heliophysics data as it makes repeated close approaches to the Sun, yielding insights across physical-space turbulence (sub-Alfvénic corona, MHD-kinetic interface) and now velocity-space turbulence as well. ## Outlook As Parker Solar Probe continues its mission with further perihelion passes, additional novel observations of the near-Sun environment are likely, contributing to ongoing solar wind and space weather research. Continued analysis of the MHD-kinetic interface, magnetic helicity structures, and velocity-space turbulent cascades may further refine models of turbulence dissipation and collisionless heating in the solar wind (arXiv:2507.13213; arXiv:2512.01492).