a magnetic circuit for establishing {HEAD ~ a magnetic field} necessary for magnetizing {TAIL ~ electrons} and preventing them from straight motion from a cathode neutralizer to anode 
a magnetic circuit for establishing { HEAD ~ a magnetic field } necessary for magnetizing { TAIL ~ electrons } and preventing them from straight motion from a cathode neutralizer to anode
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH