1. (5 points) Consider an arbitrary blob of plasma, in which a slab of electrons is pushed a small distance away from equilibrium. This results in a sort of capacitor, in which the separation of charge gives rise to an electric field. Write down the electric field between the "plates" of the capacitor, and use that field to write down the equation of motion (Newton's Second Law) for the electrons in the plasma. Show that the electrons undergo simple harmonic motion with oscillation frequency equal to the plasma frequency