1. Strictly speaking, a gamma is 1/100,000 of an oersted, the unit of measurement of the magnetic field induction, but this is not important for our considerations. When we are dealing with magnetic fields in the vacuum or in a very rarified air, the difference between magnetic induction and magnetic field intensity becomes negligible.
2. See Matsushita, S. On artificial geomagnetic and ionospheric storms associated with high-altitude explosions. - Journal of Geophysical Research, 1959, Vol. 64, No. 9
3. Mason, R. G., and Vitousek, M. J. Some geomagnetic phenomena associated with nuclear explosions. - Nature, 1959, Vol. 184, No. 4688.
4. See Leypunsky, O. I. On the possible magnetic effect of high-altitude explosions of atomic bombs. – Zhurnal Eksperimentalnoy i Teoreticheskoy Fiziki, 1960, Vol. 38, No. 1 (in Russian).
5. Kalashnikov, A. G. On observation of the magnetic meteor effect by the induction method. - Reports of the USSR Academy of Sciences, 1949, Vol. 66, No. 3