Storage Ring

The bunch's particles in transverse phase space (position across, angle up, in beam sizes), turning with the betatron tune and seen once a turn. Chromaticity smears them round the circle and gathers them again each synchrotron period; the octupoles wind them into a spiral that never comes back. The ring marks the centroid the pickup hears.

The centroid the pickup reads on each turn since the last note, in beam sizes, with the model's envelope: it fades as the particles dephase and comes back every synchrotron period.

Each note is a comb of harmonics with betatron sidebands between them. Watch the sidebands fade as the bunch drifts out of step and come back at the synchrotron period.