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where
T
e
T
e
0
,
ω
ce
ν
e
(
T
e
0
)
β
e
≈
Here, the collision frequencies are given by
ν
eno
T
e
ν
en
∼
T
e
0
.
instead of more accurate (2.1).
σ
Pe
is small for both large and small
β
e
and
maximal when
β
e
=1.
Let
β
e
(
h
0
) = 1 at height
h
0
. Since
ν
e
∝
z/l
0
) with the scale-
height
l
0
of the order of a few kilometers, then the main contribution into
σ
Pe
comes from the interval 5
exp(
−
10 km around
h
0
. With increasing of
T
e
the collision frequency goes up and
β
e
goes down. Therefore,
h
0
increases
with heating. Since the electron concentration of the
D
-and
E
-layers in-
creases with height then
σ
Pe
(
z
) also increases as it can be seen from nu-
merical calculations. For example, the unperturbed height
h
0
≈
−
70km as
for dayside as for nightiside ionospheric models. HF heating with initial
amplitude of the electric field
E
0
=0
.
5 V/m leads to increasing
h
0
to
78 km in daytime and to 87 km at night. Function
β
e
/
(1 +
β
e
) decreases
monotonically with decreasing of
β
e
. Therefore, the Hall conductivity goes
down with increasing of
ν
e
and, consequently, with decreasing of
β
e
(see
(13.5)).
Absorbtion of the pump wave in the dayside
D
-layer reduces essentially
the effect of the HF heating of
E
-layer. Figure 13.2 makes it clear that the
maximal disturbances in the ionosphere are found at local nighttime, in the
absence of the
D
. The maximum value of
δΣ
P
/Σ
P
0
, about 14%, occurs in
the right polarized wave at frequency
f
=1
2 MHz. So that the anomaly
conductivities depend weakly on
T
e
. It is, therefore, clear that excitation of
ULF-oscillations with this mechanism is low.
−
13.3 Kinetics of the E-Layer in a Strong HF-Wave
Let us consider the changes in the electron concentration within
E
-layer
caused by changes in the effective recombination rate. To clarify the role of
non-stationarity during heating of the ionospheric gas, one can consider the
chain of reactions of the chemical kinetics of the
E
-layer (see Table 13.1) ([6],
[17]).
The notation N
∗
is used in Table 13.1 for the excited nitrogen = N(
2
D
);
p
and
p
1
, are dimensionless parameters characterizing the fraction of the gen-
eration of N
4
S
= N as a result of recombination of NO
+
and collisional
dissociation of N
2
+ e. The reaction rates
γ
k
,
α
k
of Table 13.1 and all other
parameters needed to calculate the equations of chemical kinetics of the per-
turbed
E
-layer, are given in Table 13.2 ([6], [17]).
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