The picture is taken from Lightning Electromagnetics, Robert L. Gardner, 1990, p. 4. Reversing of polarity can sometimes occur probably due to an underground structure (conductive), possibly by induction in that, sometimes by the action of bipolar lightnings, whose currents may appear every time differently due to momentary mechanical condition of the plants, add and subtract with each other.
Corona surrounding Return Stroke kama ala ya kuendelea cylindrical, just katika mduara, angalia mchoro Kompletterande Model Corona, inaweza kuwa hadi umbali fulani kutoka thamani umeme channel hasi, kisha nyuma chanya (kilichorahisishwa maelezo, maalumu Ilivyoelezwa katika makala nyingi, kama vile Microsoft katika http://www.lightning.ece.ufl.edu/).