Issue I482 [81,enhancement,poisson,partiallyresolved] Refine extended to solve the Poisson Equation SIMION's electric field solver (Refine function) has been extended in SIMION 8.1.0 to support solving the Poisson Equation. As before, the Refine function can calculate potentials inside a volume defined by electrodes, but the new Poisson solving capability allows it to also handle the case when a known, arbitrary distribution of space-charge density also fills that volume (such as due to high current charged particle beams or charged insulators) For full details, see the "Poisson solver" section of the SIMION 8.1 supplementary documentation help file. See also SIMION Info:Poisson Equation ( http://www.simion.com/info/Poisson_Equation ). 2D cases implemented in 8.0.5-TEST5 (early access mode). Poisson examples updated in 8.0.4-TEST13. Formally scheduled for 8.1. Update: 2008-04-14: Fixed a fairly critical error in piclib library in the Poisson examples. The following should be added to the top of segment.other_actions (just after the "if PIC_enable == 0 then return end"): "if ion_time_of_flight <= ion_time_of_birth then return end". Update: 2010-11-10 (8.0.6-TEST10): In 2D Poisson refine, always treat left and bottom edges as mirror planes (Issue I372) Update: 8.1.0-TEST4 - 3D and anisotropic cases implemented.