APPLICATION OF THE EXACT SOLUTION FOR SCATTERING BY AN INFINITE CYLINDER TO THE ESTIMATION OF SCATTERING BY A FINITE CYLINDER

A new algorithm for cylindrical Bessel functions that is similar to th e one for spherical Bessel functions allows us to compute scattering f unctions for infinitely long cylinders covering sizes ka = 2 pi a/lamb da up to 8000 through the use of only an eight-digit single-precision machine computation. The scattering function and complex extinction co efficient of a finite cylinder that is seen near perpendicular inciden ce are derived from those of an infinitely long cylinder by the use of Huygens's principle. The result, which contains no arbitrary normaliz ation factor, agrees quite well with analog microwave measurements of both extinction and scattering for such cylinders, even for an aspect ratio p = l/(2a) as low as 2. Rainbows produced by cylinders are simil ar to those for spherical drops but are brighter and have a lower cont rast.