Study of Ionized Particles in a Gyrotron Using a Full Gyrotron Simulation Model

The ionization of the residual gas in gyrotrons causes the generation of positively charged ions and negatively charged electrons. Using the electron optics code Ariadne, it was possible to simulate the behavior of these electrons in the overall gyrotron geometry in the presence of static electric and magnetic fields as well as the electromagnetic field of the nominal transverse electric mode in the cavity. The main observation of this study is that the negatively charged electrons gain enough energy from their passage through the cavity to overcome the decelerating voltage and escape towards the collector. On the other hand, the positively charged ions remain trapped in the cavity region contributing to the neutralization effect.