It is well known that neutral atoms or molecules of various origins, e.g. interstellar, cometary, or planetary, exist pervasively in interplanetary space. When these neutral particles get sufficiently close to the Sun, they can be ionized, for example by solar ultraviolet radiation. Consequently, the freshly created ions would interact with the moving solar wind. In recent years, research in this topic area has been spurred by in site observations at comets Giacobini-Zinner and Halley and attracted considerable interest and attention from the scientific community. I this work, a series of theoretical studies will be conducted relating to ion creation and structure in the solar wind. These include (1) further studies of ion pickup and subsequent development in a solar wind, (2) problems relevant to the stability and thermalization of ions in a pickup state, (3) and possible processes leading to assimilation of the newborn ions by the solar wind. Both analytical theory and numerical simulation techniques will be used in the proposed studies. ***
