In COULOMB, when the Operation Mode is set to Phasor (Single Frequency). The electric field components will be phasors viz:

• Ε_x = a + jb
• Ε_y = c + jd
• Ε_z = e + jf

Ε_magnitude = g + jh = √ [(Ε_x)(Ε_x) + (Ε_y)(Ε_y) + (Ε_z)(Ε_z)]

Real Part {Ε_magnitude} = g
Imaginary Part {Ε_magnitude} = h
Magnitude {Ε_magnitude} = sqrt [g*g + h*h]

All the above quantities (Ε_x, Ε_y, Ε_z, Ε_magnitude ) are the rms (root mean square) values.

Let the unit vector of the normal to a surface/plane at the point of observation be {N_x, N_y, N_z}

The normal component of electric field is given by,

Ε_normal = N_x*Ε_x + N_y*Ε_y + N_z*Ε_z = {(N_x*a+N_y*c+N_z*e) + j(N_x*b+N_y*d+N_z*f)} = m + jn

Magnitude {Ε_normal} = √ [m*m + n*n]

Theoretically, on a conductor surface Ε_magnitude = Ε_normal. However, an insignificant difference (numerical noise) may exist between Ε_magnitude and Ε_normal. Therefore, Ε_magnitude on a conductor surface is also the same as Ε_normal.

In the model space at an observation point on an observation plane/surface, Ε_magnitude is not equal to Ε_normal. Therefore, in the model space at an observation point on an observation plane/surface, Ε_magnitude is the rms value of the resultant magnitude of the electric field.