Hello

I am going to simulate a Freeman ion source in Comsol.

The Freeman ion source consists of a filament, which emits electrons by heating the filament.

This filament is located in a chamber.

Also, before emitting the electron, we have introduced a neutral gas (for example, argon) in this chamber. These neutral elements are located in the chamber where the emitted electrons collide with these neutral elements and finally this collision leads to the creation of Ar+ ions.

I modeled the first part of the description above, which included the discussion of thermionics, and succeeded in emitting electrons. But I don't know how to model the second part of my explanation, which included the collision of these electrons with the neutral element argon and its transformation into argon ions. How should I model it?

Please help me.