Geoscience Reference
In-Depth Information
Electromagnetic Perturbations at the Ground Surface
We start with calculation of the jump of the potential A across the E layer. Taking
into account that the value A.0 C / can be found from Eq. ( 5.127 ) and combining
this equation with Eq. ( 5.53 ) we obtain that
LJ 1
V AI
0 m.!/
2k
ŒA.0/ D
dž.0/ A. d/ cosh .kd/ C
sinh f k.d h/ g : (5.172)
Substituting Eq. ( 5.172 ) into Eq. ( 5.167 ) and rearranging leads to
ix 0 Ǜ H
L
1 C Ǜ P /
V AI
‰.0/
dž.0/ D f;
(5.173)
where
kV AI Ǜ H v r C Ǜ P v ' A. d/ cosh .kd/ C
0 m.!/
2k sinh f k.d h/ g :
(5.174)
Here one can see an analogy between Eqs. ( 5.173 ) and ( 5.128 ), which was derived
for the plane problem. These two equations differ only in the source functions which
stay on the right-hand sides of these equations.
As has already been intimated, considering an analogy between the plane and
cylindrical problems, Eq. ( 5.168 ) can be reduced to the equation analogous to
Eq. ( 5.129 ), i.e.
B 0
f D
kV AI Ǜ P v r Ǜ H v ' ;
Ǜ H
V AI dž.0/ C
.ix 0 Ǜ P s/
L
B 0
‰.0/ D
(5.175)
Finally, one should take into account the continuity of the potential dž at z D 0.
As it follows from Eq. ( 5.132 )
A. d/ sinh .kd/
cosh Œk.d h/ :
kc 2
i!
0 m.!/
2k
dž.0/ D
(5.176)
The set of Eqs. ( 5.173 ), ( 5.175 ), and ( 5.176 ) can be solved for A. d/, dž.0/ and
‰.0/ to yield
0 m.!/ cosh Œk.d h/
2k sinh .kd/
A. d/
;
(5.177)
0 Ǜ H m.!/ cosh .kh/
2 sinh .kd/
iL
kq
‰.0/
V AI Ǜ 2 H C Ǜ P C LJ 1 Ǜ P v r LJ 1 Ǜ H v ' ;
B 0
C
(5.178)
 
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