Geoscience Reference

In-Depth Information

approximation (or tides can be assumed alternatively), and the temperature and

concentrations of the neutral components are taken from the empirical thermo-

spheric models (see foregoing). We also use these models to obtain the initial

spatial distribution of the neutral concentrations and temperature. As for wind, we

use zero velocity as the initial condition. To obtain a stationary solution we need

to integrate the modeling equation system until the results of integration remain

practically unchanged when containing the integration. Usually, to reach it, several

days (geophysical but not computing time) of integration are required.

4.2.1.2

Lower Ionosphere (D, E, and F1 Ionospheric Regions)

In this section the following parameters of D, E, and F1 ionospheric regions

are calculated: the total concentration of the molecular ions
n
(XY
C
)
D
n
(NO
C
)
C

n
(O
2
C
)
C
n
(N
2
C
), ion and electron temperatures
T
i
and
T
e
and the molecular ion

velocity
V
(XY
C
) for the height range from 60 to 175 km (for
T
i
and
T
e
) or 520 km

(for
n
(XY
C
)and
V
(XY
C
)). The following equations are solved:

@n
XY
C
=@t
D
Q
XY
C
L
XY
C

(4.8)

.3n
i
k=2/@T
i
=@t
D
P
iQ
C
P
iT
C
P
iT

(4.9)

.3n
e
k=2/@T
e
=@t
D
P
eQ
C
P
eQ
C
P
eT
C
P
eT

(4.10)

n
i
m
i
g r
.n
i
kT
i
/
X

n

in
in
n.
V
i
V
/
C
en
i
.
E C V
i
B
/
D
0 (4.11)

r
.n
e
kT
e
/
C
en
e
.
E C V
e
B
/
D
0

(4.12)

n
e
D
n
i
D
n
XY
C

(4.13)

In these equations
Q
(XY
C
),
L
(XY
C
) are the production and loss rates of the

molecular ions taking into account ionization by solar EUV direct and scattered

radiation, ionization by precipitating electrons, ion molecular reactions and dis-

sociative recombination; P
iQ
is the rate of the Joule heating of the ion gas;

P
iT
and P
iT
are the rates of the heat exchange between ion and electron and

neutral gases;
n
e
is the electron concentration; P
eQ
and P
eQ
are the rates of

heating of the electron gas by photoelectrons and by precipitating magnetospheric

electrons, respectively; P
eT
D
P
iT
; P
eT
is the rate of the elastic and inelastic

exchange of heat between electron and neutral gases;
m
i
is ion mass;
g
is the

vector of gravity acceleration;
in
n
i
D
ni
n
n
;
e
is the electron charge; and
E
,

B
are the electric and magnetic fields. More information about the terms of

Eqs.
4.8
,
4.9
,
4.10
,
4.11
,and
4.12
can be found in Namgaladze et al. (
1988
)and

Brunelli and Namgaladze (
1988
).