For the cases of monopolar and horizontal bipolar coronas, the corona equations are solved for vertical bipolar geometry without restrictions with regard to the number of subconductors. The variation of ion mobility with lifetime, as well as the change of corona onset voltage from point to point around each subconductor, are taken into account. The lateral distribution of the field intensity and current density calculated and compared with those measured experimentally. These profiles also are compared with those for a horizontal bipolar test line. The effect of applied voltage, number of subconductors and the surface factor is studied.