Proton the particles in the solar wind are electrons and protons, in approximately equal numbers. Protons also have extrasolar origin from galactic cosmic rays, where they make up about 90% of the total particle flux. These protons often have higher energy than solar wind protons, and their intensity is far more uniform and less variable than protons coming from the Sun, the production of which is heavily affected by solar proton events such as coronal mass ejections. Research has been performed on the dose-rate effects of protons, as typically found in space travel, on human health. To be more specific, there
Plasma-immersion ion implantation ( ~ l0 sec). Thus an ion matrix Debye sheath which is depleted of electrons forms around it. The negatively biased substrate will accelerate the ions within a time scale of the inverse ion plasma frequency ω ( ~ 10 sec). This ion movement lowers the ion density in the bulk, which causes the sheath-plasma boundary to expand in order to sustain the applied potential drop,in the process exposing more ions. The plasma sheath expands until either a steady-state condition is reached, which is called Child Langmuir law limit; or the high voltage is switched off as in the case