If the discharge is alone, without lateral and parallel secondary discharges (very rarely) and sufficiently precisely perpendicular, compressive forces spread from it in the first moments rather accurately in a circle shape (electromagnetic in absolute precise circle shape at any time).
Kama ni kutokwa peke yake, bila yanayovuja ulalo na sambamba sekondari (sana Mara chache) na za kutosha just perpendicular, kuenea vikosi compressive kutoka katika dakika ya kwanza badala usahihi katika sura ya mduara (katika absolute electromagnetic sahihi mduara sura wakati wowote).