Schmucker-Weidelt Lecture Notes, Aarhus, 1975 - MTNet

Schmucker-Weidelt Lecture Notes, Aarhus, 1975 - MTNet Schmucker-Weidelt Lecture Notes, Aarhus, 1975 - MTNet

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For a dipole - in z-direction this is equal to a e-kR A e -kR G = (k" - - grad-) = - curl2 (z -- 4a~k' since -kR A (e-kR/@~r~) ) = lc2e / (4aR) - -z a~ 4Ta2 - 1 I Comparison of (4.16) and (4.12) shows that for a whole space The absence of a TE-potential is clear from physical reasons, since the magnetic field of a vertical. dipole must be confined to hori- zontal planes (i.e. no vertical. magnetic field, which can only be produced by a TE-field). Using Somrnerfeld's integral, C4.17) is written The f5.el.d of a horizontal electric dipole (in x-direction, say) has both an electric and magnetic component in z-direction. Hence, a TM- and TE-potential are needed. 9 + Since ,- J%i. a2 a2 1 a2 e --kl?. m -a/ z-z ] G =-(- + -7) 4Jx=--y - -=-- I I A2e O J~ (Xr)dX cos$ Xz ax2 ay 41~k axaz R 4ak20 and we have and from then follows xsiqn(z-z ) 0 J, (Xr)dXcos$ * sign (z-zo) (4.19) f

With this knowledge of the behaviour of $,, @,, QX in the uniform whole-space, these functions for a layered medium can be easily obtained. Let in the m-th layer hm < z < hmt1 where where + -1- ~ ~ A i f i z - < z0 + -I- ~ ~ B I ~ f i > z o z - + and f-. = (z-h )Il a2 = h2-tk2. Then starting with n~ _ in n~ m m - t - + - + - + 1, A =O, B =Or BL=l1 C =I, C=O, D =01 D =I. ko 0 L 0 0 JJ 1, The boundary conditions(4.13) lead to the recurrence relations

For a dipole - in z-direction this is equal to<br />

a e-kR A e -kR<br />

G = (k" - - grad-) = - curl2 (z --<br />

4a~k'<br />

since<br />

-kR<br />

A (e-kR/@~r~) ) = lc2e / (4aR) -<br />

-z a~ 4Ta2 - 1 I<br />

Comparison of (4.16) and (4.12) shows that for a whole space<br />

The absence of a TE-potential is clear from physical reasons, since<br />

the magnetic field of a vertical. dipole must be confined to hori-<br />

zontal planes (i.e. no vertical. magnetic field, which can only<br />

be produced by a TE-field).<br />

Using Somrnerfeld's integral, C4.17) is written<br />

The f5.el.d of a horizontal electric dipole (in x-direction, say) has<br />

both an electric and magnetic component in z-direction. Hence, a<br />

TM- and TE-potential are needed. 9 +<br />

Since ,- J%i.<br />

a2 a2 1<br />

a2 e<br />

--kl?. m<br />

-a/ z-z ]<br />

G =-(- + -7) 4Jx=--y - -=-- I I A2e O J~ (Xr)dX cos$<br />

Xz ax2 ay 41~k axaz R 4ak20<br />

and<br />

we have<br />

and from<br />

then follows<br />

xsiqn(z-z )<br />

0<br />

J, (Xr)dXcos$ * sign (z-zo) (4.19)<br />

f

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