default { Beam in right circular cylinder. This is useful for obtaining beam spreading curves, for example, by adjusting the injection current and the magnetic field. } Region { Grid { J = 20 x1s = 0.0 x1f = 0.1 n1 = 1.0 K = 20 x2s = 0.0 x2f = 0.02 n2 = 1.0 Geometry=1 PeriodicFlagX1 = 1 PeriodicFlagX2 = 1 Rule { Limit n1 < 0.25 Fatal -- n1 < 0.25 grid spacing too nonuniform to ensure accuracy } Rule { Algebra J * K > 10000 Warning -- J*K >= 10000 may mean memory problems! } } Control { dt = 1.0E-12 Rule { Limit dt <= 0.0 Fatal -- time step must be positive } } Species { name = positrons m = 9.11E-31 q = 1.6e-19 } VarWeightBeamEmitter //BeamEmitter { j1 = 0 k1 = 0 j2 = 0 k2 = 10 speciesName = positrons normal = 1 np2c = 10000 I = 0.01 thetadot = 0.0 v1drift = 1e8 v2drift = 0 v3drift = 0 v1thermal = 0 v2thermal = 0 v3thermal = 0 } Conductor { j1 = 0 k1 = 10 j2 = 0 k2 = 20 normal = 1 } Conductor { j1 = 0 k1 = 20 j2 = 20 k2 = 20 normal = -1 } Conductor { j1 = 20 k1 = 20 j2 = 20 k2 = 0 normal = -1 } CylindricalAxis { j1 = 0 k1 = 0 j2 = 20 k2 = 0 normal = 1 } }