Condign volumes 1 to 3

Read from the scan by GLM-OCR; expect the odd misread word.

# UNCLASSIFIED

UK RESTRICTED

## IONOSPHERIC PLASMA

1. Formation Of Plasma Within the troposphere operate powerful processes which orientate the separation of electric charges; for example, thunder conditions give rise to huge vertical separation of charges. Meanwhile it is understood, that wind is responsible for horizontal charge distribution. When charges are displaced it is possible for the creation of image charges which make the ionospheric plasma unstable, with the result that a downward electron stream is ejected from the bottom of the ionosphere which may produce 'airglow' in a narrow high altitude band. Because these visible manifestations can be seen at night, they are often described as 'nocturnal lights'. They appear to have a close connection with one class of UAP sighting.

Figure 1 Shows the mechanism, which is explained in the following sequence:

- Due to wind over the earth's surface in a hilly region a positive charge is deposited on the hills.

- A negative charge becomes attracted to the moving air mass (shown moving to the right on the figure).

- Corresponding mirror charge images are formed with an upward E field $ \left( \mathrm{E}_{\mathrm{U}} \right) $ above the hills and a balancing downward field $ \left( \mathrm{E}_{\mathrm{D}} \right) $ restores equilibrium.

- At the ionosphere $ E_{U} $ causes instability and an electron

stream from the ionosphere is downward-accelerated by the electric force.

- 'Airglows' (UAPs) are formed when electrons are stopped in the lower atmosphere.

- The glows or 'nocturnal lights' occur in a relatively thin altitude layer and visually appear as bright spots of appreciable angular size moving across the night sky.

2. The supporting theory is explained in some detail at $ ^{1} $ It seems likely that the reports of 'silvery discs' at very high altitude are the same phenomenon. Below ionospheric altitudes researchers agree that air conductivity cannot prevent the onset of electric fields of considerable strength. In effect the middle atmosphere can become electrically de-coupled from the ionosphere. The ground and the ionosphere can be considered, in effect, two plates of an enormous capacitor. The conductivity of the ionosphere is of solar origin (hence, the investigations elsewhere in this report on possible solar flux/solar flare coonnections with the rate of UAP reports).

3. Extent The size of 'nocturnal lights', which is believed to be produced by an electron stream which penetrates to the lower atmosphere, is considerable, in order to be seen at long visual distances (slant ranges) of $ \sim 1 0 0 \mathrm{k m} $ ,where, it is calculated, the diameter can be several hundred metres. [As an example, an object of 905m diameter at 100km range has the same angular extent as that of the moon].