Investigating the role of solar wind-dust interaction in the production of He+

After leaving the relatively cool photosphere, solar material experiences a rapid increase in temperature as it travels through the dense transition region. This rise in temperature is expected to significantly ionize the majority of the material and is enough to fully ionize H and He. After entering the tenuous corona, collisions decrease and ions reach a fixed charge state where they are expected to remain as they propagate through the heliosphere. However, many eclipse observations suggest the presence low ionized and neutral material in the corona said to be due to the interaction of the solar wind with circumsolar dust. In the heliosphere, low ionized charge states are uncommon outside ICMEs; still, measurements from ACE/SWICS routinely show enhancements of He+/He2+ throughout solar cycle 23 that are potentially of solar origin, and cannot be explained with standard solar wind ionization models. Our work investigates the possible connection of the He+ enhancements detected in the heliosphere to the interaction between solar wind and circumsolar dust by modeling charge exchange of solar wind alphas with neutral H, and H₂ from the dust. This process can be further constrained and tested with coordinated observations of future DKIST and the Heavy Ion Sensor on Solar Orbiter.