Subject: Wave reflection. From: "reinifrosch@xxxxxxxx" <reinifrosch@xxxxxxxx> Date: Thu, 10 Aug 2006 20:20:08 +0200Hello again ! I just found a good introductory treatment on nearly reflection-free waves, in the book "Physics of Waves" by W. C. Elmore and M. A. Heald (Dover, New York, 1969). In their section 9.1, they show that the WKB (Wentzel, Kramers, Brillouin) approximation is reflection-free, and that it is accurate if the local wavelength lambda obeys the following inequality: (d lambda / dx)^2 << 32 pi^2 . [their equation (9.1.15)] The corresponding inequality for the local wave number k is: k^-4 * (dk / dx)^2 << 8 . Reinhart Frosch. Reinhart Frosch, Dr. phil. nat., r. PSI and ETH Zurich, Sommerhaldenstr. 5B, CH-5200 Brugg. Phone: 0041 56 441 77 72. Mobile: 0041 79 754 30 32. E-mail: reinifrosch@xxxxxxxx .