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