Correcting the record of manmade VLF radiation

The story by Charles Day (Physics Today, August 2008, page 18 ) on the effects of very low-frequency radio waves on trapped electrons in the radiation belts describes interesting results obtained on the interaction of manmade VLF radiation with radiation-belt particles. ¹

Unfortunately the Physics Today piece contains several errors.

• ▸ The absence of radiation in a region of the North Atlantic Ocean is depicted in figure 3 of Day’s story—conjugate to the region of radiation detected by the instruments of Jean-André Sauvaud and coworkers ¹ at 700 km in the South Atlantic Anomaly. That absence is not because of the loss of that radiation by precipitation into the atmosphere but because the northern particle mirror points conjugate to the South Atlantic Anomaly radiation lie at altitudes well above the altitude of the satellite carrying the instruments of Sauvaud’s team.

• ▸ In the South Atlantic in late August and early September 1958, there were three nuclear tests, not one as the author states.

• ▸ The first artificial aurora created by a nuclear test was the result of the Teak test in early August 1958, albeit at low latitudes near the Pacific test site of Johnson Island.

• ▸ The treaty prohibiting tests in the atmosphere, in space, and under water had a far more complex ancestry than just the results and effects of Starfish Prime, as stated by the author. Widespread concerns regarding the biological effects of fallout and the desire to tamp down the arms race were the major factors that led to the limited test ban treaty of 1963.