Authors: Jia Huang (SSL/UCB), the SWEAP and FIELDS teams

The slow solar wind is typically characterized as having low Alfvénicity. However, Parker Solar Probe (PSP) observed predominately Alfvénic slow solar wind (ASSW) in the inner heliosphere, with the ASSW dominating 81.6% of all the high Alfvénicity population, which is much higher than that of Helios (31.9%) and Wind (50.3%) measurements as well as the 34% of quiet-Sun-associated ASSW during solar maximum observed at around 1 au. We further separate the solar wind into fast solar wind, and slow solar wind with different Alfvénicities, and compare their differences in temperature anisotropy and alpha abundance at different heliocentric distances. Based on our analysis, we find that the ASSW seems to show an intermediate state between fast wind and slow wind with lower Alfvénicity, implying the ASSW may have multiple source regions.