Geoscience Reference
In-Depth Information
gives equations for the electron and the ion conductivities
ω
ω
+
iν
n
iν
in
,
ω
pe
4
π∆
±
ω
σ
(
±
)
e
=
i
∓
ω
ci
+
(1.76)
ω
+
ω
+
iν
n
iν
in
,
ω
pe
4
π∆
ω
σ
e
=
i
ω
ω
+
iν
n
iν
en
,
ω
pi
4
π∆
±
ω
σ
(
±
)
i
=
i
±
ω
ce
+
ω
+
ω
+
iν
in
iν
en
.
ω
pi
4
π∆
ω
σ
i
=
i
(1.77)
where
ω
pe
=4
πNe
2
/m
e
and
ω
pi
=4
πNe
2
/m
i
are squares of the electron and
ion plasma frequencies, respectively. The total conductivities are
ω
pe
4
π∆
±
ω
pe
4
π∆
σ
(
±
)
=
iω
G,
σ
=
iω
G,
(1.78)
ν
in
+
m
m
i
ν
en
−
G
=1+
m
e
m
i
+
.
(1.79)
iω
+
ν
n
Substituting (1.78), (1.79) into (1.56), we obtain the transversal and longitu-
dinal components of the complex dielectric permeability
ω
pe
∆
±
ω
pe
∆
ε
xx
∓
iε
xy
=1
−
G,
ε
zz
=1
−
G.
(1.80)
Here, the drag of the neutral component by charged plasma particles is
taken into consideration. The drag effect is important only for relatively low
frequencies
ω
ν
n
.
(1.81)
The characteristic times of the ion-neutral drag can be estimated for the
E
-
and
F
-layers as
5
10
4
s
×
E
-layer
,
2
π/ν
n
∼
10
4
s
2
×
F
-layer
.
Thus, the drag of the neutrals by charged particles should only be considered
for studying hourly variations.
'Motionless' Neutral Gas
If the frequency is much more than the collision frequency of a neutral with
all charged particles, i.e.
ω
ν
n
(
ν
n
see in (1.60)), then the contribution of
the drag of neutrals into the conductivity becomes negligible and (1.76) and
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