I am working on recreating some OML (orbital-motion limited) charging results for small spherical objects (debye/radius ratio >> 1) but have an unknown issue with my simulation.
No results are being reported over its runtime. The timesteps and timestep size are displayed but nothing else (macroparticle number/ spacecraft potential/ current on spacecraft). I only occasionally receive the error “ReciprocalFunction warning: y out of range”, but this warning has not prevented me from getting results in the past.
I am running with PIC Vol Distrib electrons and ions (two populations of each), the timesteps for the plasma and circuit solver are equal to the plasma frequency. I have increased tolerances on the Poisson solver also. Mesh quality is AWFULL (I have only gotten BAD quality at best, but the average cell quality is >0.6, which is OK according to the manual). It is also worth noting that the spherical spacecraft is 3 orders of magnitude less than the Debye length for this plasma (2e-6 m with Debye of 3e-3 m), and I have employed subdomains to bring the mesh resolution close to this scale.
No SEE, Photoemission, etc. Only charging by the PIC plasma. Conductive material is being used and there is only one node in the circuit (S/C ground).
I am wondering what could be causing this issue? Is the spacecraft simply too small? Or is the environment type not correct for a simulation of this scale (using default BiMaxwellian)? Any help would be appreciated, thank you!