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Solar Wind temperature at 1 AU exhibits statistical correlation with the magnetic structure, wherein regions with high temperature are found to be associated with coherent structures [1]. Using Parker Solar Probe (PSP) data from the first encounter, we studied this correlation between the magnetic field structure, measured using the Partial Variance of Increments (PVI) [2], and the radial temperature of the ionized hydrogen atoms (protons). For the magnetic field, we used the low cadence data from FIELDS instrument and for proton temperature we used the moments data from SWEAP. We observed that the probability distribution function (PDF) of events with high PVIs have a higher median temperature than those with lower PVI, implying the presence of heating mechanism in the solar wind, associated with turbulence driven structures. [1] Osman, K. T., Matthaeus, W. H., Greco, A., & Servidio, S.2011, ApJ, 727, L11 [2] A. Greco, W. H. Matthaeus, S,. Perri, K. T. Osman, S. Servidio, M. Wan and P. Dmitruk, Space Sci Rev., 214, 1 (2018)

During the Parker Solar Probe's (PSP) first perihelion pass, the spacecraft reached to within a heliocentric distance of ~37 solar radii and observed magnetic and flow structures characterized by sharp gradients. As we try and understand these intermittent coronal structures better, an important property to examine is their degree of correlation. To this end, we use the well-tested Partial Variance of Increments (PVI) technique [1] to identify intermittent events in FIELDS and SWEAP observations of magnetic and velocity fields. We then examine the distributions of waiting times between events with varying separation and PVI levels. We find power-law distributions, suggesting a high degree of correlation that may originate in a clustering process, as opposed to a random distribution produced by a memory-less Poisson process [2]. We also find that waiting times between events with separations larger than inertial-range scales follow a power-law close to -1, hinting at a possible connection with observations of "1/f noise" associated with signals originating near the source solar surface [3]. The present study complements the one by Dudok de Wit et al., which focuses on the waiting times between the observed "switchbacks" in the radial magnetic field. [1] Greco et al. Space Sci. Rev. (2018) 214:1 [2] Greco et al. Phys. Rev. E (2009) 80, 046401 [3] Matthaeus & Goldstein PRL (1986) 57, 4

During the first two orbits of Parker Solar Probe (October 2018-May 2019), recurring solar wind stream flows were sequentially observed at one astronomical unit (AU) by ACE, at L1, and STEREO-A, ~108°-92° eastward from the Sun-Earth line. Compression regions characterized by magnetic field and density enhancements were observed at the leading edge of these solar wind streams. At one AU they were often accompanied by increases of energetic (>50 keV) ion intensities, as is typical of compression regions. In this paper, we associate the recurrent solar wind streams observed at one AU with those observed by the Parker Solar Probe (PSP). The association allows us to investigate the plasma and energetic particle properties of the interface between slow and fast streams at different solar distances. Our associations are supported by predictions made by the ENLIL model using GONG-ADAPT-WSA which allows us to contextualize the inner heliospheric conditions during PSP's first two orbits.

Alfv'enicity is an important concept in plasma dynamics, but its meaning is sometimes ambiguous, as it is used to imply different (related) constructs by different authors. There are three measures: Alfvén ratio r_A

Convection and rotation drive the solar dynamo and, ultimately, provide the mechanical energy flux required to heat the solar corona and accelerate the solar wind. However, the way in which energy is then dissipated to heat the corona and wind are not well understood. Some energization models invoke non-thermal energy flux imparted by plasma Alfvén waves, while others rely on a carpet of small nano-flares as energy input, however these models have been unconstrained by direct measurements of the solar wind near its origin. Here we use in situ measurements from the FIELDS instrument suite during the first solar encounter (E1) at 35.7 solar radii (Rs) of the NASA Parker Solar Probe (PSP) mission to reveal the magnetic structure and kinetics of slow Alfvénic solar wind emerging from a small, equatorial coronal hole. Our measurements show that, at solar minimum, the slow wind can escape from above the low-lying, complex magnetic structures of the equatorial streamer belt, carrying a magnetic field that is highly dynamic, exhibiting polarity reversals on timescales from seconds to hours. These rapidly oscillating field structures are associated with clustered radial jets of plasma in which the energy flux is dramatically enhanced and turbulence levels are higher. Time intervals between groups of jets indicate a solar wind that is steady with a mostly radial magnetic field and relatively low levels of Alfvénic turbulent fluctuations. This 'quiet' wind however shows clear signatures of plasma micro-instabilities associated with ion and electron beams and velocity-space structure.

Observations at 1 AU have reported direct evidence of an inertial-range energy cascade [1]. The average value of energy cascade rate in 1 AU solar wind plasma is around 1000 J/kg/s, which is shown to be sufficient to account for the heating of the solar-wind [2]. Parker Solar Probe (PSP) offers the first opportunity to estimate a similar, fluid-scale energy decay rate closer to the solar corona. Using a Politano-Pouquet [3] third-order law, we provide estimates of fluid-range energy cascade rate at 50 to 36 solar radii, during the first perihelion first encounter of PSP. Despite the cross-helicity being high in these regions of the heliosphere, there is an inertial-range cascade occurring. The energy transfer rate is at least 100 times higher than the average value at 1AU. Further, we estimate the global energy decay rate at the energy-containing scales using a Taylor-Karman decay phenomenology [4]. The von Karman energy decay estimates agree reasonably well with the third-order-law estimates. We also compare the two estimates with the heating rate obtained from a turbulence-based, global solar wind simulation [5]. [1] Sorriso-Valvo et al., Phys. Rev. Lett., 99, 115001 (2007) [2] MacBride et al., ApJ, 679, 1644 (2008) [3] Politano & Pouquet, GRL, 25, 273 (1998) [4] Wan et al., JFM, 697, 296315 (2012) [5] Usmanov et al., ApJ, 865, 25 (2018)