Wideröe — constant E in gaps (sin ωt, alternating by gap) · relativistic RK4 · decoupled display · particle source · multi-gap
First gap is centered at x=0. Additional gaps are appended to the right with mid tubes between gaps. Adjacent gaps alternate polarity (odd = +, even = −). E is constant in each gap and sinusoidal in time; E=0 in tubes.
βλ/2 helper uses half first kick: Kn=(n−½)·|q|·Vpeak and γ from chosen m.