Inner Source Pickup Ions from Chondritic Smooth Interplanetary Dust Particles

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Abstract Inner source pickup ions (PUIs) are thought to be produced by the interaction between solar wind ions and interplanetary dust particles (IDPs). The amount of PUIs produced and their velocity distribution depend on the composition, density, porosity, and size of the IDPs. Quinn et al. simulated the production of PUIs from chondritic porous (CP) IDPs. The study showed that the composition of PUIs produced from CP IDPs nearly resembled the solar wind. The purpose of this study is to expand upon Quinn et al. to chondritic smooth (CS) IDPs to get a more complete description of inner source PUI production. We simulate the production and transport of C+ and O+ PUIs using the Stopping and Range of Ions in Matter and the Energetic Particle Radiation Environment Module. We consider five production mechanisms: solar wind recycling, neutralization, backscattering, sputtering, and sputtering-induced recycling. Comparisons are made to observational studies that used the Charge-Time-Of-Flight instrument on board the SOlar and Heliospheric Observatory. Results indicate that sputtering is the dominant mechanism. This results in an inner source PUI composition that resembles the dust grains, which are rich in species such as C and O and poor in species such as Ne. However, studies by Ulysses show that inner source PUIs produced inside of ∼0.5 au have a composition similar to that of the solar wind. Thus, we conclude that the IDP population close to the Sun is dominated by CP IDPs rather than CS IDPs.