We used the streamaligned magnetohydrodynamics (SAMHD) model to simulate Carrington rotation 2210, which contains Parker Solar Probe’s (PSP) first perihelion at 36.5
 Award ID(s):
 1836821
 NSFPAR ID:
 10321308
 Date Published:
 Journal Name:
 The astrophysical journal
 Volume:
 926
 ISSN:
 20418213
 Format(s):
 Medium: X
 Sponsoring Org:
 National Science Foundation
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Abstract R _{⊙}on 2018 November 6, to provide context to the in situ PSP observations by FIELDS and SWEAP. The SAMHD model aligns the magnetic field with the velocity vector at each point, thereby allowing for clear connectivity between the spacecraft and the source regions on the Sun, without unphysical magnetic field structures. During this Carrington rotation, two stream interaction regions (SIRs) form, due to the deep solar minimum. We include the energy partitioning of the parallel and perpendicular ions and the isotropic electrons to investigate the temperature anisotropy through the compression regions to better understand the wave energy amplification and proton thermal energy partitioning in a global context. Overall, we found good agreement in all in situ plasma parameters between the SAMHD results and the observations at PSP, STEREOA, and Earth, including at PSP’s perihelion and through the compression region of the SIRs. In the typical solar wind, the parallel proton temperature is preferentially heated, except in the SIR, where there is an enhancement in the perpendicular proton temperature. This is further showcased in the ion cyclotron relaxation time, which shows a distinct decrease through the SIR compression regions. This work demonstrates the success of the Alfvén wave turbulence theory for predicting interplanetary magnetic turbulence levels, while selfconsistently reproducing solar wind speeds, densities, and overall temperatures, including at small heliocentric distances and through SIR compression regions. 
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