Answer to Question #180 in Electromagnetism for bruce
Cosmic rays consist mostly of protons, middle energy ξ of which consists of few billions of electron volts. Intensity I stream of protons, reaching Earth's atmosphere is equal approximately to one proton on square centimeter per second. To evaluate the time needed for protons of cosmic rays raised the Earth’s potential so they could not reach Earth’s surface because of electric repulsion. Explain, why even after that time protons of cosmic rays reach Earth’s surface.
t = ξ/(4πRle²) ≈ 10^6 ≈ 10, (R - Radius of the earth, e- proton charge, numerical answer is gotten when ξ/e ~ V). In fact the earth’s potential can not reach such value, together with protons coming exists reverse process in which Earth’s atmosphere loses positive charges in the form of protons and positive ions, dispersing in space under the influence of aroused electric field.