Simulation of pin-cathode - anode discharge arc with CST PS

I would like to simulate the electron current flow that passes through a pin-cathode and a grounded anode plane in the case of a spark discharge.

Does anybody have any hint on how to properly set up the particle source on the pin tip and what would be the best parameters for the model?

I do set up two potentials, the -V of the cathode (e.g -100kV) and 0 V for the ground plane and activate them as a tracking field.

A parameter that I would like to include is a DC-like emission process, for instance a given (estimated) current amount that would be emitted from the cathode.

Re: Simulation of pin-cathode - anode discharge arc with CST

are u using the PIC solver?
I have tested this solver and consequently this type of DC emission, but as far as i know the current for DC emission is fully dependent on the cathode and anode surfaces and also the gap volume!
And something more: do you really want to have arc discharge?! So your gap material should not be vacuum! U should have some kind of gas for your gap! how do u want to define it? Or may be u want to have some kind of field-included emission?

Re: Simulation of pin-cathode - anode discharge arc with CST

To get better results for the vacuum diode with explosive electron emission, one has to put into account the gap surface expansion and closure effects due to cathode and anode plasmas.
Time dependend solids that serve as particle emitters might work well in such an approach, although i dont think the suite is able to do that.

What i do, is, for various setups of anode plane and cathode "ball", is to get the total emitted current from the tracking solver, and put it in the pic solver (the dc emission), but this always seems to be over the space charge limiting current (SCL current), so the pic solver seems to not work after a while (particles having a hard time to leave the surface of the cathode). The estimation of the true SCL current is difficult, and i have a hope that the tracking solver may be somehow correct, but the pic solver is then working a bit strangely.

PIC solver doesnt seem to work well with zero energy cathode emission and field acceleration towards the anode. Maybe i am putting way much emitted current. To get an SCL beam though, i sometimes just define a surface that just emits electrons in some desired speed (let's say 100keV) and send them to the rest of the structure.