Interplanetary hydrogen and helium from cosmic dust and the solar wind

Interplanetary dust grains saturated with solar wind gases may act as sources of H and He in the inner solar system. Calculations for the density and fluxes of these gases are given in terms of the basic dust size distribution function. Owing to the lack of agreement between the different experimental data, it is not possible to fully assess the importance of this process. By using the data available, H and He densities in the ranges 8×10−7 to 6×10−3 cm−3 and 6×10−8 to 5×10−4 cm−3 can be predicted at 1 AU. Depending on the true effective area of the dust particles, the higher He densities could be adequate to explain the presence of 4He+ in the solar wind.