Reflection or inversion of rays in planes of reflection symmetry in a magnetic field.
(For magnetic fields in CPO2D and CPO2DS, see magnetic 2D fields.)
After a magnetic field (in CPO3D) has been specified (even a field with zero strength) the user is asked to specify the reflections of the rays.
The reflections that are specified can be either:
(1) Compounded (that is, combined) to make a single operation (that is, they are not taken separately in sequence) and are applied to the x = 0, y = 0, z = 0 and x=y planes to create new rays. This is the usual option because in a magnetic field the rays usually have inversion symmetry. For example if the magnetic field is in the z direction and a certain ray passes through a series of points with coordinates (x,y,z), then a second ray that passes through the points (-x,-y,z) is also a valid ray. This second ray is obtained from the first simultaneously transforming x to -x and y to -y to give a single operation -unlike the reflections in the absence of a magnetic field, which remain separate operations. It is not possible to incorporate all the relevant safeguards into the program, so the user should carefully inspect the three 2-dimensional plots of reflected rays to check on the symmetries.
(2) Or treated separately, as when there is no magnetic field (by disabling the ‘compound’ option).
Return to general note on symmetries.