Alpha Particle Content in the Solar Wind as Observed by the SPAN-Ion Instrument on Parker Solar Probe

The SWEAP/SPAN-Ion instrument on Parker Solar Probe (PSP) measures ion distribution functions in the Solar wind, and in addition is equipped with a time of flight analyser allowing heavier ions to be distinguished from protons. Despite a large proportion of the core ion distributions still being outside the instrument's field of view, it is possible to make good measurements of the proton and alpha moments, particularly of velocity and temperature, in directions dictated by the sensor geometry and field of view. Having carried out a careful subtraction of the small contamination in the instrument's alpha channel from protons, we present here first results on the alpha particle content in the solar wind, as observed by SPAN-Ion, during PSP's second encounter from 55 to 35 Solar radii. In particular we report on alpha to proton abundance ratios, both inside and outside the magnetic "switchbacks" observed by the FIELDS instrument suite, alpha particle velocities, and alpha to proton temperature ratios. Wavelet spectra of the FIELDS magnetic field measurements reveal an abundance of ion cyclotron waves. While these are most likely due to secondary proton beams, we examine whether or not a proton alpha drift instability is an additional driver of these waves.