The solar wind is plasma, i.e., an ionized gas that fills the solar system. It results from the supersonic expansion of the solar corona. The solar wind consists primarily of electrons and protons with a smattering of alpha particles and other ionic species at low abundance levels. The structure of the heliosphere is strongly affected by the protons produced by the photo-ionization of the interstellar neutral hydrogen and by the charge exchange of the hydrogen atoms. The wavelet is a new analytical tool for turbulent or chaotic data to the physics community. It allows detection and characterization of short-lived structures in turbulence. Proton density fluctuations are studied using discrete wavelet transforms.