by the United States, as the Limited Test Ban Treaty came into effect shortly thereafter. Research directions The United States completed six high-altitude nuclear tests in 1958, but the high-altitude tests of that year raised a number of questions. According to U.S. Government Report ADA955694 on the first successful test of the Fishbowl series, "Previous high-altitude nuclear tests: Teak, Orange, and Yucca, plus the three ARGUS shots were poorly instrumented and hastily executed. Despite thorough studies of the meager data, present models of these bursts are sketchy and tentative. These models are too uncertain to permit extrapolation to other altitudes and yields with any confidence. Thus there is a strong need, not only for better instrumentation, but for further tests covering a range of altitudes and yields." There were three phenomena in particular that required further investigation: The electromagnetic pulse generated by a high-altitude nuclear explosion appeared to have very significant differences from the electromagnetic pulse generated by nuclear explosions closer to the surface. The auroras associated with high-altitude nuclear explosions, especially the auroras that appeared almost instantaneously far away from the explosion in the opposite hemisphere, were not clearly understood. The nature of the possible radiation belts that were initially generated along the magnetic field lines connecting the areas of the auroral displays were also poorly understood. Areas of blackout of radio communication needed to be understood in much more detail since that information would be critical for military operations during periods of possible nuclear explosions. The Fishbowl tests were monitored by a large number of surface and aircraft-based stations in the wide area around the planned detonations and also in the region in the southern hemisphere in the Samoan Islands region, which was known in these tests as the southern conjugate region. Johnston Island is in the northern hemisphere, as were all of the planned Operation Fishbowl nuclear detonation locations. It was known from previous high altitude tests, as well as from theoretical work done in the late 1950s, that high-altitude nuclear tests produce a number of unique geophysical phenomena at the opposite end of the magnetic field line of the Earth's magnetic field. According to the standard reference book on nuclear weapon effects by the United States Department of Defense, "For the high-altitude tests conducted in 1958 and 1962 in the vicinity of Johnston Island, the charged particles entered the atmosphere in the northern hemisphere between Johnston