The effect of microwave frequency and grad B on the energy of electrons in an electron cyclotron resonance ion source

In an electron cyclotron resonance ion source the energy of the electrons is increased by the electric field of the microwaves. The gyrofrequency of the electrons has to be in resonance with this field. The production of highly charged ions requires very energetic electrons. As a consequence, the acceleration of electrons by the microwaves has to be efficient. In this article the energy gain of the electrons due to the microwaves has been studied. The gradient of the magnetic field and the frequency of the microwaves were the main variables. The simulations show that more efficient heating is achieved with higher microwave frequency and with smaller gradient of the magnetic field.