Solar Wind Alpha Composition Using SPC on Parker Solar Probe

Parker Solar Probe (PSP) is a mission designed to explore properties of the solar wind closer to the sun than ever before. Up to now, detailed particle observations from the Solar Probe Cup (SPC) have primarily focused on examining the proton population in the solar wind. However, several periods throughout the PSP mission have indicated that SPC has also observed a pronounced and distinctive alpha population. Properties of minor ions, like He++, are imprinted with properties of the solar wind's source region as well as mechanisms connected to the heating and acceleration of the solar wind making them sensitive markers of its origin and formation at the Sun. Through a detailed analysis of the alpha velocity distribution functions, this work examines periods where significant and persistent alpha peaks are observed with SPC to determine characteristics of the solar wind stream. We compute the He++ abundance as well as examine the velocity, temperature, and magnetic field properties throughout those periods to identify distinctive solar wind features that can provide insight to their solar source. Initial results show that the He++ abundance observed with PSP is consistent with measurements observed with instruments near 1 au. This work is supported by the NSF-REU solar physics program at SAO, grant number AGS-1850750.