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1. Solar Spicules, Filigrees, and Solar Wind Switchbacks

   https://doi.org/10.3847/1538-4357/ad23e0  

   Lee, Jeongwoo ; Wang, Haimin ; Wang, Jiasheng ; Wang, Meiqi ( March 2024 , The Astrophysical Journal)

   Spicules, the smallest observable jetlike dynamic features ubiquitous in the chromosphere, are supposedly an important potential source for small-scale solar wind transients, with supporting evidence yet needed. We studied the high-resolution Hαimages (0.″10) and magnetograms (0.″29) from the Big Bear Solar Observatory to find that spicules are an ideal candidate for the solar wind magnetic switchbacks detected by the Parker Solar Probe (PSP). It is not that spicules are a miniature of coronal jets, but that they have unique properties not found in other solar candidates in explaining solar origin of switchbacks. (1) The spicules under this study originate from filigrees, all in a single magnetic polarity. Since filigrees are known as footpoints of open fields, the spicule guiding field lines can form a unipolar funnel, which is needed to create an SB patch, a group of field lines that switch from one common base polarity to the other polarity. (2) The spicules come in a cluster lined up along a supergranulation boundary, and the simulated waiting times from their spatial intervals exhibit a number distribution continuously decreasing from a few seconds to ∼30 minutes, similar to that of switchbacks. (3) From a time–distance map for spicules, we estimate their occurrence rate as 0.55 spicules Mm⁻²s⁻¹, which is sufficiently high for detection by PSP. In addition, the dissimilarity of spicules with coronal jets, including the absence of base brightening and low correlation with EUV emission, is briefly discussed.

    

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2. Slow solar wind modeling of the Metis/Solar Orbiter – Parker Solar Probe quadrature

   https://doi.org/10.1088/1742-6596/2544/1/012007  

   Adhikari, L ; Zank, G P ; Telloni, D ; Zhao, L -L ; Pitna, A ( July 2023 , Journal of Physics: Conference Series)

   Abstract In January 2021, Metis/SolO and PSP formed a quadrature from which the slow solar wind was able to be measured from the extended solar corona (3.5 – 6.3 R ⊙ ) to the very inner heliosphere (23.2 R ⊙ ). Metis/SolO remotely measured the coronal solar wind, finding a speed of 96 – 201 kms −1 , and PSP measured the solar wind in situ, finding a speed of 219.34 kms −1 . Similarly, the normalized cross-helicity and the normalized residual energy measured by PSP are 0.96 and -0.07. In this manuscript, we study the evolution of the proton entropy and the turbulence cascade rate of the outward Elsässer energy during this quadrature. We also study the relationship between solar wind speed, density and temperature, and their relationship with the turbulence energy, the turbulence cascade rate, and the solar wind proton entropy. We compare the theoretical results with the observed results measured by Metis/SolO and PSP. 

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3. Supporting Parker Solar Probe mission with Goode Solar Telescope at Big Bear Solar Observatory

   https://doi.org/10.1117/12.2628741  

   Cao, Wenda ; Yurchyshyn, Vasyl ; Yang, Xu ; Cho, Kyung-Suk ; Wang, Haimin ( August 2022 , Proc. of SPIE)

   Evans, Christopher J. ; Bryant, Julia J. ; Motohara, Kentaro (Ed.)
4. An Empirically Driven MHD Model to Predict the Solar Wind at Parker Solar Probe and Solar Orbiter during the Current Solar Minimum

   Kim, T. K. ; Pogorelov, N. ; Arge, C. N. ; Jones-Mecholsky, S. I. ( December 2020 , American Geophysical Union, Fall Meeting 2020, abstract #SH021-08)

   null (Ed.)

   Since the launch on 2018 August 12, the Parker Solar Probe (PSP) has completed its first five orbits around the Sun, having reached down to ~28 solar radii at perihelion 5 on 2020 June 7. More recently, the Solar Orbiter (SolO) made its first close approach to the Sun at 0.52 AU on 2020 June 15, nearly 4 months after the launch. Using a 3D heliospheric MHD model coupled with the Wang-Sheeley-Arge (WSA) coronal model using the Air Force Data Assimilative Photospheric flux Transport (ADAPT) magnetic maps as input, we simulate the time-varying inner heliosphere, including the trajectories of PSP and SolO, during the current solar minimum period between 2018 and 2020. Above the ADAPT-WSA model outer boundary at 21.5 solar radii, we solve the Reynolds averaged MHD equations with turbulence and pickup ions taken into account and compare the simulation results with the PSP solar wind and magnetic field data, with particular emphasis on the large-scale solar wind structure and magnetic connectivity during each solar encounter. 

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5. Solar Wind Simulations along the Parker Solar Probe Trajectory

   Hegde, D. V. ( December 2021 , AGU Fall Meeting 2021, held in New Orleans, LA, 13-17 December 2021, id. SH55C-1858.)