Geoscience Reference
In-Depth Information
Fig. 5.8
Dependence of the
ionizing UV radiation source
on altitude
600
J
uv
(h)
1
cm
3
s
400
200
0
0
50
100
150
h, km
J
rays
.h/
D
C
rays
N.h/
1
cm
3
s
N.0/
; C
rays
2;
(5.10)
These factors (UV radiation of crown and cosmic rays) are sufficient for
maintenance of the E-layer and weak ionization of mesosphere and stratosphere. At
great altitudes and in the polar areas, the processes of ionosphere formation are also
determined by events in the magnetosphere. For their description, more complicated
models are required.
The ionization balance of stratosphere, mesosphere, and ionosphere is defined by
three equations: balance of positive ions, balance of negative ions, and a condition
of charge quasi-neutrality:
J
UV
.h/
C
J
rays
.h/
ˇ
i
n
C
n
ˇ
e
n
C
n
e
D
0
.K
a
.T
e
/
C
K
3
.T
e
/
N.h//
N.h/
n
e
ˇ
i
n
C
n
D
0
n
e
C
n
n
C
D
0
(5.11)
where ˇ
e,i
D
coefficients of electron-ion and ion-ion recombination, and
K
a
and
K
3
D
constants of dissociation and three-body attachment reactions, depending on
electron temperature, which are determined by the ratio of electric field and gas
concentration
E/N
. The solution of system (
5.11
) is shown in Fig.
5.9
.
At night the
E
-layer is recombining:
n
e
day
1
C
n
e
day
ˇ
e
t
:
n
e
right
.t/
D
(5.12)
In Fig.
5.10
the calculated distributions of electron concentration for
daytime and nighttime are compared with well-known results of observations
