Results of non-stationary simulation of helical electron beams (HEBs) param
eters based on the PIC method and a quasi-stationary model of the electric
field are presented. Evolution of the distribution function of electrons f(
v(perpendicular to)) over their oscillatory velocities is studied. Bombardm
ent of the cathode by reflected electrons is studied. (C) 1999 Elsevier Sci
ence B.V. All rights reserved.