In this paper, we present a statistical validation of the DSCOVR solar wind data in the operational space weather archive. The DSCOVR observations of the interplanetary magnetic field (IMF), solar wind velocity, density, and temperature were hourly averaged and compared to measurements from NASA’s ACE and Wind spacecraft. Hourly averages, in general, show good correlations between the satellites for the IMF, solar wind velocity GSE vx-component, and density. During the period covered by this study (spanning from late July 2016, when DSCOVR went operational, to the end of 2020), the DSCOVR products show no clear evidence of permanent degradation. However, for plasma parameters there were periods of disagreement with ACE and Wind. The correlation coefficients (Pearson’s r) calculated over the entire study period were similar or the same between DSCOVR versus Wind and DSCOVR versus ACE. For comparisons between DSCOVR and Wind, the IMF Bx and By GSE r were 0.94 and 0.96, respectively, while r for the IMF GSE Bz-component was 0.88. For solar wind velocity, r was found to be 0.96 for the GSE vx-component, compared with 0.30 for vy and 0.33 for vz. For density, r was found to be 0.84. DSCOVR density observations tend to overestimate compared to Wind values when the solar wind densities are low (below ∼5 /cc), while agreement between the two spacecraft on IMF measurements tend to increase with decreasing spatial separation.

We report observations of reconnection exhausts and associated ion and electron separatrix layers in and around the Heliospheric Current Sheet (HCS) during PSP Encounters 08 and 07, at 16 Rs and 20 Rs. HCS reconnection accelerated protons to almost twice the solar wind speed and increased the proton core energy by a factor of ~3, due to the Alfvén speed being comparable to the solar wind flow speed at these near-Sun distances. During E08, accelerated protons were found to have leaked out of the exhaust along separatrix field lines, appearing as field-aligned energetic proton beams in a broad region outside the HCS. Concurrent dropouts of strahl electrons, indicating disconnection from the Sun, provide further evidence for the HCS being the source of the beams. Around the HCS in E07, there were also proton beams but without electron strahl dropouts, indicating that their origin was non-local and closer to the Sun.