The main fix here is to project the external field, now a potential, with EvalOnNodes rather than ProjectOnBasis. This removes a grid-scale mode that shows up when using external fields. I wonder if this was the source of problems in the nonlinear stage of some ion acoustic turbulence simulations when @nmandell tried to put them on a GPU a year or two ago.
this goes with gkylzero PR #211 (https://github.com/ammarhakim/gkylzero/pull/211)
The main fix here is to project the external field, now a potential, with EvalOnNodes rather than ProjectOnBasis. This removes a grid-scale mode that shows up when using external fields. I wonder if this was the source of problems in the nonlinear stage of some ion acoustic turbulence simulations when @nmandell tried to put them on a GPU a year or two ago.