Authors: A. R. Poppe and C. O. Lee

The collisional grinding of interplanetary meteoroids should continually produce grains over a wide range of sizes, including down to the nanometer-size regime. Once generated, nanodust grains are subject to interplanetary electromagnetic forces from the solar wind due to their relatively large charge-to-mass ratios, resulting in complex and highly time-dependent dynamics. Here, we use the coupled Wang-Sheeley-Arge solar corona/Enlil solar wind models together with a nanodust charging and dynamics model to explore the behavior and variability of nanodust dynamics in the inner heliosphere (<1 au) both within and across multiple solar cycles. In particular, we quantify the relative accessibility of these grains to 1 au across solar cycles 23 and 24, including focusing and defocusing heliospheric conditions. Finally, we qualitatively compare our model results with STEREO A (STA)/WAVES observations and identify correlations between the STA/WAVES single-hit rate and the relative flux of >10 nm grains. Using solar cycle 23 as a proxy for the behavior of solar cycle 25, since both solar cycles share the same defocusing-to-focusing transition, we predict the relative flux of nanodust grains in the future and identify times at which nanodust impacts may reappear in the STA/WAVES dataset. Continued analysis of future STA/WAVES observations will provide an important test of this prediction, either bolstering or weakening the interpretation of electromagnetically accelerated nanodust grains as the source of single-hit events in the STA/WAVES Time Domain Sampler dataset.