The discussion revolves around the relationship between the energy density of electromagnetic (EM) waves and their amplitude, specifically addressing why the energy density is proportional to the amplitude squared. Participants explore the implications of this relationship in the context of varying frequencies and charge acceleration.
Participants appear to disagree on the implications of the relationship between amplitude and energy density, particularly regarding the influence of frequency on average energy density. The discussion remains unresolved with multiple competing views presented.
There are unresolved questions regarding the dependence of energy density on frequency and the relationship between charge acceleration and electric field amplitude. Participants have not reached a consensus on these points.
The reason the energy density of an EM wave is proportional only to the amplitude squared is because electromagnetic energy density U is:
U = (E2 + B2)/2
in units where c = μ0 = ε0 = 1
The average value of E2 is proportional to Emax2, it doesn't matter how fast E is varying, so the average energy density doesn't depend on ω.
Hurkyl
-> http://electron9.phys.utk.edu/optics421/modules/m1/production.htmThe electric field is also proportional to the acceleration of the charge. The larger the acceleration, the larger is the field.