Hydro- and Electrodynamics of the Midlatitude Ionosphere - The Earth's Ionosphere: Plasma Physics and Electrodynamics - page 246

600

Total

Gravity

Pressure

500

Wind

400

300

Electric field

200
2

200 2 100 0 100 200

Vertical velocity (m/sec)

Figure 5.13 Magnitudes of the four contributions to the vertical plasma flow velocity
over Arecibo for a typical plasma density profile, neutral wind, and zonal electric field
component. (Data supplied by R. Burnside and R. Behnke.)

January 8-9, 1970

V ||

V

⊥ N

20

0

2 20

12 14 16 18

Local time

20 22 24 26

Figure 5.14 Example of the observed anticorrelation between components of plasma
drift perpendicular to B (positive is geomagnetic northward) and parallel to B . (Here and
in most Arecibo plots a positive V ||

−

B .) [After Behnke and Harper
(1973). Reproduced with permission of the American Geophysical Union.]

is upward along

geomagnetic meridian plane—that is, between the components antiparallel and
perpendicular to B . The resulting vector plasma motion was therefore nearly
horizontal, which shows that vertical balance does often occur. The parallel and
perpendicular dynamics, which seem so nicely separated by the dominance of
the magnetic field effect, are thus not at all decoupled. Just as with the neutral