Proving Vector Potential Pump Amplitude-Intensity Relationship

[cetmoimonsieur]

Homework Statement

Prove that the relationship between the dimensionless amplitude a of a wave and the intensity I of the wave is given by:

Homework Equations

B = curl (A)
B: Magnetic Field
A = [mass of electron * c / e ]*a*e^[i*(kx-wt)]
where k is the wavenumber and is given by: 2pi / wavelength of laser
I = c*B^2 / (magnetic permeability of free space)
Hint: div(A) = 0 will give a unique solution for B

The Attempt at a Solution

Honestly I do not know where to begin. Take the divergence of the equation of A and find a solution for B? I am not sure.

 

[cetmoimonsieur]

Sorry to bump this thread, but does anyone have an idea?