3 Pitfalls and Limitations
A loose collection of pitfalls that may be difficult to avoid. In particular, new users may find these notes useful, but experienced users can also benefit from them.
3.1 Hard Edge Fields
Fields that feature steps, such as hard-edge fringe fields, are strongly advised against. In sector magnets where particles have different path lengths inside the magnet, they are kicked one, two, or even more steps differently depending on position and momentum. Combined with large time steps, this can lead to visibly split beams and other artificial effects.
3.2 Very Short Active Elements / Large Time Steps
This is closely related to the hard-edge problem. It concerns elements that model electromagnetic devices whose lengths are very short and comparable to the time step. In this case, a split of the bunch can be observed because some particles are kicked more often than others. The time step should then be reduced to mitigate the effect.