On the possibility of solar dust ring formation due to increased dust-ion drag from coronal mass ejections

Model calculations of circumsolar dust are conducted taking into account the increased ion drag due to the interaction of F-coronal dust with CMEs inside 8Rs. The choice of 8Rs is not arbitrary, after considering the severe plasma environment inside this region. Dust particles are allowed to spiral inward towards the Sun via the Poynting-Robertson drag, and the characteristics of the CMEs are applied in order to numerically compute the increased ion drag on F-coronal dust. The results show that the spiraling time would roughly be cut in half for dust particles inside 8Rs. Differences in the spiraling time due to the dependence of the magnitude of increased ion drag on dust particle size, creates separation in the heliocentric distance of the orbits of small (> 10 μm) vs. larger particles. This result could create conditions where a dust ring or rings may appear as a transient feature, which would explain former citing of such dust rings by observers and their absence by others.