In the XZ view E-field surface plot what component is visualized? I know it plots the z and x axis but what does the color map?
By default, the visualizer will plot the magnitude of the field. You can select a specific component in the “Attributes” section, “Vector operation”:
or also plot |E|^2 (in "scalar operation, choose “abs^2”). You will find most of the information you need about the visualizer here.