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There is a fundamental difference between the classical expression for theretarded electromagnetic potential and the corresponding retarded solution ofthe wave equation that governs the electromagnetic field. While the boundarycontribution to the retarded solution for the potential can always be renderedequal to zero by means of a gauge transformation that preserves the Lorenzcondition, the boundary contribution to the retarded solution of the waveequation governing the field may be neglected only if it diminishes withdistance faster than the contribution of the source density in the far zone. Inthe case of a source whose distribution pattern rotates superluminally (i.e.,faster than the speed of light in vacuo), the boundary term in the retardedsolution governing the field is by a factor of the order of R^(1/2) larger thanthe source term of this solution in the limit where the distance R of theboundary from the source tends to infinity. This result is consistent with theprediction of the retarded potential that the radiation field generated by arotating superluminal source decays as 1/R^(1/2), instead of 1/R. It alsoexplains why an argument based on the solution of the wave equation governingthe field in which the boundary term is neglected, such as Hannay presents inhis Comment, misses the nonspherical decay of the field.

Response to "Comment on `Method of handling the divergences in the  radiation theory of sources that move faster than their own waves'" [J. Math.  Phys. 40, 4331 (1999)]