The solar wind H and He content

Charge exchange collisions between interplanetary neutral H atoms and solar wind protons may lead to fluxes of neutral H atoms and He⁺ ions in the solar wind. Photoionization of interplanetary helium atoms may also contribute to the He⁺ flux. The expected fluxes of He⁺ ions and neutral H atoms in the solar wind are computed. A simple model is used to compute the intensity of resonantly backscattered solar Hell (λ304 Å) and Lyman α radiation.