Short Wave Radiation Problems in Inhomogeneous Media: Asymptotic Solutions

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522 Clifford O. Bloom Nicholas D. Kazarinoff

Short Wave Radiation Problems in Inhomogeneous Media: Asymptotic Solutions

Springer-Verlag Berlin.Heidelberg. New York 1976

Authors Clifford O. Bloom Nicholas D. Kazarinoff Department of Mathematics State University of New York at Buffalo Amherst, N. Y. 14226/USA

Library of Congress Cataloging in Publieation Data

Bloom, Clifford O 1935The asymptotic solution of h~h-frequency radiationscattering problems in inhomogeneous media. (Lecture notes in mathematics ; 522) Includes index. I. Radiation. 2. Scattering (Physics) 3. Asymptotic expansions. I. Kazarinoff, Nicholas D., joint author. II. Title: The asymptotic solution of highfrequency radiation-scattering problems ... III. Series: Lecture notes in mathematics (Berlin) ; 522. QA3.L28 no. 522 tQC~753 510'.8s E539'.2~ 76-17818

AMS Subject Classifications (1970): 35B40, 35B45, 35J05, 53C25, 78A05, 78A40 ISBN 3-540-0?698-0 Springer-Verlag Berlin Heidelberg 9 New 9 York ISBN 0-387-07698-0 Springer-Verlag New York Heidelberg 9 Berlin 9 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. Under w 54 of the German Copyright Law where copies are made for other than private use, a fee is payable to the publisher, the amount of the fee to be determined by agreement with the publisher. 9 by Springer-Verlag Berlin 9Heidelberg1976 Printed in Germany Printing and binding: Beltz Offsetdruck, Hemsbach/Bergstr.

PREFACE

These notes are based upon a series of lectures given at the University of Oxford, Spring,

1975 by the second author.

The authors

tunity for their joint work to be presented

thank Dr. J. B. McLeod for the oppor-

in his seminar.

These notes are primarily concerned with existence, and the rigorous

asymptotic

Au+~2n(x)u

(p)

for

= f(x)

l

large, Here 5V C R m

V

estimates by a variation of ness of the solution approximate construct

u

solution

(x 6 ~v),

m-I 2 rlUr- i~,u+--~--r u dS = 0

In Chapter K

9 Friedriehs'

abc-method.

of the boundary-value

(in p o w e r s of

there an approximate

on

5V .

problem

L2

These estimates (P)

l-i ) to the problem

of

u

We apply the a priori point-wise

expansion of the exact solution as high-frequency

and

above.

(P)

a priori

imply unique-

We construct

in Chapter 3.

an

We also

solution to the more. general radiation-scattering

in Chapter 3 that the approximate

amplitude

convex or star-shaped

I we obtain new point-wise

problem where the values of a linear combination prescribed

(Ixl = r)

is the exterior of a not necessarily

(m = 2 or 3) .

a priori estimates,

problem:

(x 6 V) ,

u = u0(x) lira ~ R-k= r=R

body

uniqueness,

solution of the radiation-scattering

and its normal derivative estimate of Chapter

solution to the problem I 4 =

(P)

This asymptotic

are

I to prove

is an asymptotic

approximation

yields