Notes

1.

The beam charge must be specified via a CHARGE element somewhere upstream in the beamline. Unlike ZLONGIT and ZTRANSVERSE, IMPEDANCE has no deprecated charge parameter; omitting the CHARGE element is an error.

2.

Only file-based impedances are accepted; the broad-band resonator inputs of ZLONGIT and ZTRANSVERSE are not implemented. A resonator can be pre-tabulated onto a fine frequency grid (with one of elegant’s helper scripts) and loaded through INPUTFILE.

3.

Output of the per-channel wake potentials to the file named by WAKES is available only in the serial version, as for ZLONGIT and ZTRANSVERSE. When written, one V _t column is emitted per enabled channel (VtZL, VtZxD, VtZyD, VtZxQ, VtZyQ).

4.

The original ZLONGIT and ZTRANSVERSE elements are unchanged and remain available.

5.

Bunched-mode application is available via BUNCHED_BEAM_MODE=1; see Section 6.

6.

Numerical equivalence with stacked ZLONGIT + ZTRANSVERSE is exact to round-off for the transverse channels. For the longitudinal channel, IMPEDANCE uses the bin-center convention of ZTRANSVERSE rather than the left-edge convention of ZLONGIT; this yields physically equivalent results that differ at the half-bin sampling level (typically ~ 10^-6 relative).