How use velocity vector in field definition

Dear All,

I want to use velocity vectors as a variable component in electric field definition, something like this :

fix 3 all efield v_vx 0.0 0.0

Should I use any specific command, what it should be.

Any help would be highly appreciated,


Not sure what you are asking. The doc page for the fix efield
and variable commands give lots of details on this.