THE METHOD OF CURVED ELECTRICAL PROBES 227 



OPERATIONAL DISTANCE AND DIMENSIONS OF THE AZIMUTHAL 

 ARRANGEMENT 



The operational distance R of the azimuthal arrangement is taken as 

 equal to the length of the three-electrode limiting AMN arrangement 

 which on the surface of a horizontally homogeneous medium gives a KS 

 value, coinciding wth that for an azimuthal arrangement. 



The KS value for an azimuthal arrangement is determined from the 

 formula 



Qn = A J , (5) 



"where: K is tlie coefficient of the azimuthal arrangement. 



For a limiting 3-electrode AMN arrangement, the KS value will be 



Q = 2nR^^, (6) 



where: E is the intensity of the field of the point source; 



R is the length of the 3-electrode arrangement (the distance from 

 the point source to the center of the measuring dipole). 



Let R be the operating distance of the azimuthal arrangement. Hence 



Qa = Q' (7) 



Starting from equation (7) we will attempt to show the connection be- 

 tween the operating distance of the azimuthal arrangement and its dimen- 

 sions. 



According to the principle of reciprocity 



^ Kl = uiF-uiF = ^ u'Jb-^u^b- (8) 



Here the lower indices indicate the points and arrangements of the obser- 

 vation, the upper indites the points and arrangements of supply. 

 It is obvious that: 



B 



A 

 A 



where: E^^, E^^ are the components of the field of the point sources M 

 and TV along the direction AB. 



To de'.e-mine the values of the field E of the point source we return to 



15* 



