I want to carryout beam dynamics simulations using code ASTRA, where I want use a 3m long 2856 MHz traveling wave linac. As per ASTRA manual "The field table has to contain the on-axis longitudinal field amplitude of at least one RF period plus the input and output coupler cells, which are treated as standing wave cells. To the file a first line is added, containing in z1, z2, n, m"

Should I simulate a unit cell with input and output cells, then save the standing wave field data or should I simulate separately a input and out cell and a unit cell ?

For unit cell, I should take from half cell (middle to one cell)+iris+one full cell+iris+half cell (middle of next cell)?