Xmpl2d22, 22nd 'example' data file for CPO2D
Parallel edge deflector, planar symmetry.
The following data were obtained when the memory and speed of PC's was much more limited than at present, so the available number of segments was small and the requested inaccuracies were fairly high to give a quick demonstration.
Two semiinfinite, coplanar plates with parallel edges are used to deflect a beam.
Here 'planar' symmetry is used, so that the system extends an infinite distance in the +/ y directions.
For plates that have a separation 2s (where s = 0.5 in the present example), and that have potentials +/V, the potential at a general point (x,z) is:
(2*V/pi)*arcsin(sqrt((tsqrt(T**24*x**2*s**2))/(2*s**2)))
where
t = (x**2+z**2+s**2).
On the z axis the potential is zero and the transverse electric field is
(2*V/pi)/sqrt(z**2+s**2).
Values calculated by the program conform to these expressions, within the stated inaccuracy.
A beam of 7 rays that initially converge to the point (0,12) is set up.
After deflection the rays converge to the point (0.9991,11.72). The deflection voltage of 0.0374 is chosen to give a deflection of approximately 2s. The spread in the x direction is approximately 0.00030.
Comparison of 3 deflectors:

Type 
V 
x 
z 
dx 
xmpl2d21 
Wire 
.1274 
.9906 
11.15 
.0018 
xmpl2d22 
Edge 
.0374 
.9991 
11.72 
.00030 
xmpl2d23 
Plate 
.0274 
.9992 
11.48 
.00028 
See 3D deflectors for a comprehensive comparison of deflectors.