Resolved Question

Hi
I had not heard of it so I looked it up. Hope this helps:
Operation Argus was the only clandestine test series in the 17 year history of atmospheric testing. It was secretly conducted in the South Atlantic, 1100 miles southwest of Capetown, South Africa. Argus consisted of three very high altitude test shots of the W-25 warhead to investigate the effects of nuclear explosions outside of the atmosphere - how the charged particles and radioactive isotopes released would interact with the Earth's magnetic field which could potentially interfere with radar tracking, communications, and the electronics of satellites and ballistic missiles.

In a way, these tests could be considered a logical extension of the high altitude shots conducted within the atmosphere in Hardtack I which detonated warheads at 85,250 feet (a 1.7 kt W-25 in the Yucca shot), 141,000 feet (a 3.8 Mt W-39 in the Orange shot), and 252,000 feet (also a 3.8 Mt W-39 in the Teak shot). Argus pushed nuclear tests still higher with effects tests at 100 miles (528,000 feet), 182 miles (961,000 feet), and 466 miles (2,460,000 feet).

The motivation for this secret series was a theory developed by the brilliant but eccentric physicist Nicholas Christofilos at Lawrence Radiation Laboratory (LRL). He had predicted that military significant effects would be produced by injecting charged particles from nuclear explosions into near space to create artificial Van Allen belts. This series sought to prove (or disprove) his theory by actually creating such a belt. Operation Argus has been termed the "world's largest scientifc experiment" encompassing as it did the space surrounding the entire Earth. The tests essentially confirmed his predictions.

I do not know what the South African Anomaly is either. Perhaps you meant South Atlantic? That is where the tests were conducted.
:)