G.J. Stoney:

Decomposed the scalar potential into bidirectional wave pairs.

"On a Supposed Proof of a Theorem in Wave-motion"
 Philosophical Magazine, 5(43), pp. 368-373 (1897),
and several other papers

E.T. Whittaker:

Decomposed the scalar potential into a series of bidirectional EM wave pairs in harmonic series, where the two waves in each pair are conjugates (i.e., a wave/antiwave pair) and are longitudinal waves.

"On the partial differential equations of mathematical physics,"
Math. Ann., Vol. 57, 1903, p.333 - 355.

Showed that all classical EM – including waves – can be replaced by two interfering scalar potential functions.  (This founded superpotential theory, extended by Nisbet, Bromwich, McCrea, and others.)

"On an expression of the electromagnetic field due to
electrons by means of two scalar potential functions,"
Proc. Lond. Math. Soc. Series 2, Vol. 1, 1904, p. 367 - 372.

R.W. Ziolkowski:

Independently rediscovered the biwave decomposition of the scalar potential and added the product set (in theory enabling modulations and communications) to Stoney and Whittaker's sum set.

Various papers. 1985 to date.

© T.E.BEARDEN