On Nov 22, 2012, at 4:07 PM, Kerem Yunus Camsari wrote: > I have a doubt regarding the solution I obtain from FiPy in a specific > problem I am attempting. > I am solving the 1-Dimensional Fokker-Planck Equation Using FiPy. > > <PastedGraphic-1.tiff> > > G^n(x) is the electron-density in my model. D_2 (x) is the Diffusion > coefficient, D_1(x) is the Drift coefficient. > Because the Diffusion coefficient is inside the derivative operator, I need > to include another convection term to solve this equation with FipY: > > <PastedGraphic-2.tiff>
You have swapped D_1 and D_2 between the first and second equations. > The diffusion coefficient I use is usually a function of position, and > sometimes go to zero in the middle of the grid. > In this case, I expect the electron density (G^n(x)) to go to zero, because > there can be no current when the diffusion coefficient reaches zero inside > the grid. That might be so, but I don't see that it has to. d^2/dx^2(D_2(x) G^n(x)) == 0 just says the curvature of D_2(x) G^n(x) is zero, but says nothing about the value of G^n(x). _______________________________________________ fipy mailing list [email protected] http://www.ctcms.nist.gov/fipy [ NIST internal ONLY: https://email.nist.gov/mailman/listinfo/fipy ]
