continue until the energy of the electrons was dissipated by collisions
with other slower electrons and ions which normally inhabit the space
above the earth.
The experiment bore out the theoretical predictions of Christofilos
in a beautiful manner and provided scientific information of great value
about conditions surrounding the earth. The electrons were observed by
means of four counters in the satellite Explorer IV, which had been
prepared with this experiment in mind, The counting rate was transmitted by radio to microlock and minitrack stations on the ground and
recorded on tapes.
Many other observations in connection with the experiment were
made near the launching site and also near the so-called "conjugate
point" to determine the effect of the phenomenon on the ionosphere,
Not all of these results are yet available. A significant check on the
Explorer IV data was provided by sounding rockets carrying radiation
measuring apparatus. Three shots in all were fired from the USS Norden
Sound, separated by a few days. The first was apparently low in altitude
but the other two were placed as planned. The best observations were
obtained from shot HI,
Military Significance
A nuclear explosion in space produces three kinds of effects of
military importance. The high energy radiation including particles from
the explosion produces effects in space; the whirling high energy electrons
generate radio noise; and the delayed radiation from the fission products
can affect radio transmission,
All of these effects are matters of degree, depending on yield,
location and geometrical considerations,
All of the effects are bounded by about 70° magnetic N, latitude.
}
The effects are also limited by the tendency of the pressure of the
products of the explosion to 'burst'' the earth's magnetic field. Too large
a nuclear explosion would expel the bomb debris through a temporary
4
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"crack" in the field. 7”
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It is doubtful if any long-lived effects can be produced nearer to the pole
than this limit.
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