Condign volumes 1 to 3

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

## DETECTABILITY OF PLASMA TARGETS

1. If it is assumed that, in the first instance the target is a spherical plasma body, the following conditions could exist:

- The sphere could be large in dimension compared with the radar wavelength

- The radar echoing area of the simple sphere is a function of its ratio of circumference to the illuminating wavelength $ [ 2 \pi a / \lambda $ (where a is the sphere radius)]

- For large values of $ 2 \pi a / \lambda $ the RCS approaches the optical RCS ( $ \theta $ a $ \theta $ )

- The sphere, if homogeneous and perfect would be aspect-insensitive.

2. In theory it is seen, therefore, that if a UAP was a stable plasma sphere of adequate electron density, a metre in diameter and comprised of entirely reflecting gaseous material, then its maximum radar echoing area for all practical purposes, when illuminated by a E/F Band(0.10m) radar, could be about ~16 square metres. For D/E(L) Band radars the value computes to five square metres. However, there may be several other factors of importance for a plasma UAP which could significantly affect its detectability; and in practice (as mentioned at page 5-3, paragraph 12), the real values (L Band) are estimated as falling somewhere between -60dB (0.000001m $ ^{\circ} $ ) and +8m $ ^{\circ} $ . Any surface absorption of the radar signal, which, in theory, should have little effect when the wavelength is large compared to the target dimensions, is not necessarily the case here, as it is by no means certain that the UAP plasma (inside it's outer shell, or surface) can be considered a resonant body. Or, indeed, that it's surface remains a consistent and constant reflector, especially as many UAP reports indicate that the body is constantly changing colour and often varying slightly in shape. The response of the body as a reflector when compared against the characteristics of the radar is clearly a key factor. (R)

3. Target Characteristics Target RCS fluctuation plays a significant role in the detection performance of all radars. In general, radars, (apart from Weapon Control/Tracking Radars, which may dwell for relatively long periods on their chosen target) inspect their targets at repeated and sometimes regular intervalsin the form of dwells or scans, and by illuminating them with bursts of pulses. If it is reasonably assumed that a plasma UAP is a cloud of swirling ionised gases with variable electron density (possibly interspersed with periods of greater plasma stability), then for much of the time the radar reflectivity may vary rapidly, possibly uniquely from pulse-to-pulse (Swerling Case 2), rather than from scan-to-scan (Swerling Case 1). Further, the fluctuations may vary continuously from scan-to-scan (Case 3); or finally, so rapidly as to vary from pulse-to-pulse (case 4).

4. If the plasma entity has several, possibly variable-density cores (as sometimes visible and reported as variable colour centres within a single buoyant body, and as always the case where a UAP comprises a grouping of multiple bodies (e.g. 'Triangle', 'Oblong', or Balls either 'in a row', or 'stacked'), this further adds to the complexity and variability of any radar reflecting characteristics the