Source Materials and Heating of Alfvénic Slow and Hot Solar Wind Revealed by Heavy Ions

Abstract This work quantitatively studies the differences of heavy ions among non-Alfvénic slow wind (N-ASSW), classical fast wind (FSW), and Alfvénic slow and hot wind (ASSW and AHSW) by effect size and Kolmogorov–Smirnov statistic. Statistics of ACE measurements in solar cycle 23 show that He/O and Fe/O in ASSW and AHSW are significantly similar to those in N-ASSW, but are distinct from FSW. The mean Fe 16+ /Fe 13+ in ASSW (AHSW) is in the middle of the two mean values of FSW and N-ASSW. However, Fe 16+ /Fe 13+ in the three categories of solar wind are similarly low during solar minimum. Charges of C and O ions in ASSW and AHSW are significantly different from those in FSW during solar minimum, but have obvious overlaps to those in FSW during solar maximum. Besides, the speed ratio of He 2+ , C 5+ , O 6+ , and Fe 10+ against protons is studied, and that of O 6+ in ASSW and AHSW is most like that in FSW. AHSW has two peaks of proton specific entropy showing negative and positive relations to electron temperature. The results support that ASSW, AHSW, and N-ASSW experience the same fractionation in the chromosphere. The heating in ASSW (AHSW) differs from N-ASSW between the freeze-in heights of O and Fe during solar maximum, possibly caused by interchange reconnection. The preferential acceleration of heavy ions may be proportional to the gyroradius scale. Dissipation of Alfvén waves to electrons may happen in AHSW.