Dynamics and Electrodynamics of the Mesosphere - The Earth's Ionosphere: Plasma Physics and Electrodynamics - page 360

Positive ions

Negative particles

1

Neutral particles Electrons

0.1

Positive particles

0.01

0.01 0.1 1

Ionization rate (cm 23 s 21 )

10 100

Figure 7.15a Charge distribution for 3000 particles cm − 3 at 85 km. Particle

radius = 1 nm.

Negative particles

Positive ions

Neutral particles

1

Positive particles

Electrons

0.1

0.01

0.01 0.1 1

Ionization rate (cm 23 s 21 )

10 100

Figure 7.15b Charge distribution for 3000 particles cm − 3 at 85 km. Particle radius =

10 nm. [After Reid (1990). Reproduced with permission of the American Geophysical
Union.]

are thought to be associated with smaller ice particles, the simultaneous lidar
and radar data in Fig. 7.14 are in excellent agreement with this scenario
(Lübken et al., 1996). The charged particles enhance radar scattering, leading
to PMSE.
But what is the origin of these small particles? Reid (1990) used the calculations
of meteoric dust or smoke particles supplied by Hunten et al. (1980), which is
reproduced in Fig. 7.16. Here the dust concentration is plotted versus particle
radius at 90 km. This was determined using meteor impact and recoagulation
theory as originally suggested by Rosinski and Snow (1961). Dust detectors
have now been flown on sounding rockets, and we are just beginning to measure
the earth's dust and dusty plasma layers (Havnes et al., 1996; Gelinas et al.,
1998). Recently, based on an idea by Cho et al. (1998), Strelnikova et al. (2007)
used the Arecibo incoherent scatter radar to detect dust. R. Varney (personal