{HEAD ~ Two electrodes} each having an electrode tip at a mutual distance EA are arranged inside {TAIL ~ the discharge vessel} 
are arranged inside
{ HEAD ~ Two electrodes } each having an electrode tip at a mutual distance EA are arranged inside { TAIL ~ the discharge vessel }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL