magnetic poles placed at exit part of ion source and {HEAD ~ a magnetic pole} in {TAIL ~ a center} of a discharge channel in a form of protrusion with a magnet or electromagnet placed in a central magnetic pole 
in
magnetic poles placed at exit part of ion source and { HEAD ~ a magnetic pole } in { TAIL ~ a center } of a discharge channel in a form of protrusion with a magnet or electromagnet placed in a central magnetic pole
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH