Question: Does the Hybrid-PIC solver include relativistic ion dynamics?

[ZLBEST001]

Hi WarpX community,

I am currently using the Hybrid-PIC solver in WarpX to study the cosmic-ray streaming instability (CRSI). I would like to clarify whether the current Hybrid-PIC implementation includes relativistic ion dynamics.

Thank you very much for your help.

[roelof-groenewald]

Hi @ZLBEST001. Thank you for your question. The hybrid-PIC model does include relativistic dynamics, in the sense that the Boris pusher used to update particle positions respects relativistic effects and the current deposition uses the proper particle velocities (relativistically corrected). Keep in mind though that the Ohm's law model used to update the E-field explicitly assumes there is no displacement current, so light waves do not propagate within that model (Whistler waves are the highest frequency modes).

[ZLBEST001]

Thank you very much for your explanation and for taking the time to answer my question.
Your clarification was very helpful and has given me a much better understanding of the hybrid-PIC implementation in WarpX. I really appreciate your help!