An electric field accelerates {HEAD ~ ions} and {TAIL ~ electrons} in directions parallel to the electric field 
An electric field accelerates { HEAD ~ ions } and { TAIL ~ electrons } in directions parallel to the electric field
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH