DYNAMICS OF THE SPACE-CHARGE-LIMITING CURRENT IN GYRO-TYPE DEVICES

The Air Force Research Laboratory is investigating the dynamic interac tions which occur between the growing electromagnetic waves generated in a gyro type device, and an electron beam (e-beam) with nonzero perp endicular velocity operating near the space-charge-limiting current. P article-in-cell (PIC) codes are used to perform simulations of the tra nsverse electric (TE)(01) mode, and results are presented, Initial res ults show that beams of this nature suffer from a time-dynamic onset o f the space-charge-limiting current instability at values below those predicted from analytic theory, This produces a beam time-dynamic puls e shortening, thus placing an upper limit on the power and pulse lengt h of gyro-type devices.