I have been wondering how an atom is ionized and multiply ionized in an electric field? In a single ionization, does only one electron go through each transition until it is ionized? What about in a multiple ionization? Would the first electron travel through all transitions while the other electrons remain at their ground state? And after the first ionization will the next electron travel through it's transitions until it becomes ionized etc etc? Or will all the valence electrons travel through their transitions and become ionized at the same time?