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This is Volume 2 of the Ministry of Defence report 'Unidentified Aerial Phenomena in the UK Air Defence Region', Defence Intelligence Staff Scientific and Technical Memorandum 55/2/00, dated February 2000 and received 7 December 2000. It gathers 25 working papers on natural and man-made phenomena, meant as a reference for analysing UAP reports. The papers cover ball lightning, radar detection, balloons, satellites, mirages, plasma and similar subjects. One paper compares magnetic field experiments on human volunteers with close encounter reports. It concludes that effects from such fields are 'uncannily similar' to what witnesses describe.
“Sea”13 pages
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11. Associated with the size is the electron line density (ELD). These are classed as either 'over' or 'under' dense: Under-dense ELD is $ 50^{\circ} $ Viewing conditions must also be correct to observe a satellite:
- It is unlikely in daylight.
- Its size must be large (small debris is not seen).
- The light falling on the satellite, which is then reflected must be adequate. Other data concerning the observation of satellites and hence the probability of being mis-reported as UAPs, is at Working Paper No.17.
## PLASMAS, CHARGED AEROSOLS AND SPRITES
17. It is evident that when plasmas, particularly sprites and any higher altitude phenomena, which depend on luminosity due to electrical charges, that sightline rates can be extremely high. These phenomena, often described as 'nocturnal lights' are described at Working Papers Nos. 2, 5, 19, 21, and 24. They frequently appear as having significant angular size and, because of their high speeds (despite being at altitudes from a few kilometres to tens of kilometres), are often Document, cited by the archive. The PDF is mirrored here; the original link is under it. The text was read from the page images by an OCR model; expect the odd misread word. 258 pages are in the text index: search them above, or from the library's search.