Plasma consists of electrons and heavy positively charged ions. The number of electrons and ions per unit volume is the same and is equal to n. In a plasma layer of thickness h, all electrons were given the same velocity v in the direction perpendicular to the layer. After what time will the main mass of electrons be stopped by electric forces if: a) v ≫ hϵ0mne2; b) v ≪ hϵ0mne2, where e, m are the charge and mass of the electron? Estimate the frequency of the electron oscillation in both cases.
227