ELECTRICAL CHARACTERISTICS OF A LOW-PRESSURE WIRE DISCHARGE AND AN APPLICATION TO HIGH-CURRENT DENSITY ELECTRON-GUN

The electrical characteristics of a wire discharge plasma were investi gated, in particular, taking notice of the effect of electron trapping by axial magnetic fields. It was found that the plasma property chang ed remarkably, when the magnetic fields were applied. This property ma y be used to control the wire discharge plasma. The wire discharge pla sma plays an important part as an ion source of an ion-induced seconda ry emission electron gun. This type of electron gun was demonstrated. The maximum electron beam current obtained was 90mA/cm(2) at beam ener gy of 100keV. In our calculation model, the secondary emission coeffic ient gamma is 12.0 for 100keV helium ion and the electron beam extract ion efficiency beta obtained is 0.35.