Ionization by electric discharge

[zenineasa]

Hello everyone,

Thank you for reading my question.

I am looking to model and simulate ionization of hydrogen using a high volate DC source connected to two parallel plates. I am thinking about having some hydrogen particles generated and sent from one side, which enters a uniform electric field.

Could you let me know if this is an approach that would work and can be done with WarpX? Also, is there a better approach to perform the same?

Regards,
Zenin

[RemiLehe]

@zenineasa
To make sure I understand: is the plan to have the particle injector emit neutral hydrogen, and then use our field ionization module to ionize these particles?
If yes, then I think that this could be done in WarpX. You could look at this example to see how to setup field ionization:
https://github.com/ECP-WarpX/WarpX/tree/development/Examples/Tests/ionization

[zenineasa]

@RemiLehe ,
Thank you for your response. The plan is indeed to emit neutral hydrogen. But the idea is to use DC electric field to perform ionization. I see that the example you suggested use a laser, which, according my current understanding, has AC electric field that causes the ionization. I read the following wikipedia article, which suggests that there is some difference in ionization using AC and DC electric fields.
https://en.wikipedia.org/wiki/Tunnel_ionization

Can we work with DC electric field in WarpX to simulate ionization of hydrogen?

[RemiLehe]

Thanks for following up.

WarpX's field ionization module uses the ADK ionization model, which I think should work both for DC field as well as AC field -- provided that the frequency of the AC field (a laser in the above example) is much smaller than the frequency associated with the ionization energy (E_ionization / h). This is because, in my understanding, ADK theory assumes that the field seen by the atom varies slowly in time.

[zenineasa]

Thank you for the information!

[ax3l]

Just adding:
Although this is initially field ionization, be careful if a true discharge-driven ionization happens (from strong currents) that you might want to estimate of collisional ionization becomes relevant in this scenario, too.