It has been proposed by M. Evans that there
exists a longitudinal field associated with circularly polarized radiation,
called B3. Certain experiments are interpreted by Evans as being exhibitions of
a chiral Inverse Faraday effect. As Faraday phemomena are associated with
magnetic fields, then for the effect to be Faraday related, there must exist a
longitudinal B field. Evans devises arguments to say that the effect is
proportional to the formula A^A* where A is a complex vector potential. Evans
makes many claims about his formulas.
A test of his formulas and claims is made in the accompanying pdf file. The
results indicate that sometimes his claims are valid and sometimes they are not.
In the examples used to compute the results of his formulas, no longitudinal
magnetic field derived from a curl of a vector potential was ever obtained. In
other words, it would appear that the claim of a longitudinal magnetic field, a
magnetic field of the type defined in conventional electromagnetism, is
MISLEADING. Certainly, there can arise non-zero terms due to A^A* which indeed
can be longitudinal, but they do not appear to this writer to have anything to
do with conventiaonal magnetism.
Either the theory of electromagnetism has to be modified, or there is an
alternative explanation. Evans suggests that electromagnetic theory must be
revised, to incorporate a longitudinal magnetic field - B3.
HOWEVER: Consider the alternative interpretation. Assume that there is some chiral effect due to a term A^A*. Can this interaction produce a chiral effect that is not related to magnetism? Yes, in fact a simple explanation that does not require a longitudinal B field would be to assume that the chiral effect A^A* is a form of OPTICAL ACTIVITY. The chiral effect is not a FARADAY effect at all. Recall that Optical Activity is related to the magnetization induced by E fields, while Faraday effects are due to magnetization induced by B fields. Then, a non-zero A^A* that produces a chiral effect, does not have to be associated with a longitudinal magnetic field. Such an interpretation makes better sense in light of the examples computed in the accompanying pdf file.
With this interpretation, possible effects due to a chiral interaction of the form A^A* (if they exist) do not require a revision of electromagnetic theory.
There exists other electromagnetic phenomena whereby the magnetic field
irreducibly will have three components, and therefor one would expect true
longitudinal components of the B field. These field structures can have a Hopf
Invariant, of the type described by Ranada .
It would appear that such structures have nothing to do with the Evans-type
theory of B3.