My simulation in lammps to apply external cyclic electric field is prompted: Dump custom fix does not compute per-atom info; how do I solve this problem? Do I need to add any commands?
First you need to isolate the issue. Your reported error is about a dump command and not about applying an electric field.
Without more specific information it is near impossible to provide specific advice.
Well, you obviously have to remove the f_Etetra references from your dump command. You can only dump per-atom data.
In that case, how do I output the value of the electric field?
There are multiple ways to output data with LAMMPS: 8.3.1. Output from LAMMPS (thermo, dumps, computes, fixes, variables) — LAMMPS documentation
For example, you can output global scalar values as thermo output or with fix print.
Thank you for your help and answers!