Computing plane waves with the magnitude constant to 1

I have a question. In regards with the given computation,

u0[r_, phi_] := Sum[I^(-n) BesselJ[n, r] Exp[I n phi], {n, -5, 5}]; {Plot3D[Re[u0[r, phi]], {r, 0, 4}, {phi, 0, 2 Pi},    ColorFunction -> Hue],       Plot3D[Im[u0[r, phi]], {r, 0, 4}, {phi, 0, 2 Pi},        ColorFunction -> Hue]} {Plot3D[Abs[u0[r, phi]], {r, 0, 4}, {phi, 0, 2 Pi},    ColorFunction -> Hue, PlotRange -> All],   Plot3D[Arg[u0[r, phi]], {r, 0, 4}, {phi, 0, 2 Pi},    ColorFunction -> Hue, PlotRange -> All]} 

which is in Cartesian coordinates, the magnitude of the series for the plane wave must be constant 1. How do I set this in the given code?

Thanks