We revisit the Fourier transform of a Hankel function, of considerable importance in the theory of knife edge diffraction. Our approach is based directly upon the underlying Bessel equation, which admits manipulation into an alternate second order differential equation, one of whose solutions is precisely the desired transform, apart from an a priori unknown constant and a second, undesired solution of logarithmic type. A modest amount of analysis is then required to exhibit that constant as having its proper value, and to purge the logarithmic accompaniment. The intervention of this analysis, which relies upon an interplay of asymptotic and close-in functional behaviors, prompts our somewhat ironic, mildly puckish caveat, our negation "not" in the title. In a concluding section we show that this same transform is still more readily exhibited as an easy byproduct of the inhomogeneous wave equation in two dimensions satisfied by the Green's function G, itself proportional to a Hankel function. This latter discussion lapses of course into the argot of physicists and, in its rôle of a mere afterthought, makes no claim whatsoever to any originality.

We examine herein a simple model for the evolution in time of the pressure which a suddenly vaporized, ablating layer exerts upon the subjacent body. The model invokes a plausible construct of surface material instantaneously thrust into a gaseous regime governed by a Maxwell-Boltzmann phase space distribution. The surface pressure per se is gotten by computing the time rate of change of the momentum per unit area which the retrograde molecules, and only those, transfer through impact/reflection to the unvaporized body below. An explicit pressure formula, one alluding to the variable gas temperature within the vaporized layer, is obtained as a single quadrature requiring numerical integra- tion at finite times past the onset of impact. Limiting, null pressure values, both close-in and in pulse aftermath, can nevertheless be extracted in analytic terms, confirming in particular the indispensable asymptotic evanescence. A universal formula in dimensionless variables is given for pressure versus time, both suitably normalized.