﻿724 Mr. A. Bramley on Radiation. 



Then 



E ^— 1 r — Rcosfli 



R " 4tt ' V fl^gs ' (r 2 + E 2 + z 2 -2rK cos 6^ 



4/r * y/l^P' {r 2 +R 2 + z 2 -2rU cos^)^' 

 ™ <? — ^ 1 1 



~ 4tt * "c 2 " ' VwF 2 ' (r 2 + R 2 + * 2 -2rRcos0 1 ) 1/2 

 1 + /3 2 ^ Rsin^ 



and H^ = 0, 



<? /3 r — R cos 0'i 



H 2 = 



47T* v /r r ^ 2 '(^ 2 + R 2 + ^ 2 -2rRcos(9 1 ) 3 / 2 ' 



4tt* Vl^^X^ + RS + * 2 - 2rRcos 0i) 3/2 

 e m 1 1 



4tt * wc ' VT 3 ^ 2 ' ( r2 + R 2 + 2 2 - 2rli cos tfj) 1 /* ' 



where r 1 = (? i2 + R 2 + 2' 2 — 2?^R cos ^!) 1/2 = distance from the 

 electron's centre to the point in question. 



The calculated values of H and E along the axis of 

 revolution agree with those found by other means except for 

 the terms involving the accelerations. 



It will be observed that this part of the force varies in- 

 versely as the square of the distance of the point from the 

 moving charge, and is therefore inappreciable at great 

 distances. 



Turning to the part of the intensities which involves the 

 accelerations we have two components, 



E -- e ~ {l l 



4tt* c 2 ' V1-/3 2 ' (r 2 + R 2 + ^ 2 -2rRcos6' ] ) 

 Ty e — u 1 



1/2' 



R "" 4tt ' uc ' s/T^^ ' if + R" + z 2 - 2rR cos 9^ ' 



Thus we see that the part of the electromagnetic field which 

 depends on the acceleration of the particle is specified by 

 two vectors, the electric and magnetic intensities. These 

 are mutually perpendicular but not equal in magnitude, 

 except for the special case that n — c. There is another 

 important difference between the part of the field which 

 depends on the acceleration and that which does not; in the 



