Recent Results on K-Shell Ionization by Ion Collisions
The experimental K-shell ionization cross sections of 48Cd, 50Sn, 52Te, 53I and 56Ba for alpha particles, between 2.2 MeV and 2.8 MeV, and of 52Te for protons, between 1.6 and 3 MeV, are presented. The justification for making these measurements comes, on the one hand, in filling a region where, at present, data are sparse: for example, 52Te ionization cross sections by alpha particles have never been reported before, and, on the other hand, checking between previously reported and diverging sets of experimental results: for example, for alpha particles on tin. In addition, the K-shell ionization cross sections of 52Te for protons can be considered as an extension of Khelill's measurements.
K-shell x rays of selected elements from Nb through Gd for incident protons and alpha particles from 0.6 to 2.4 Mev
K-shell x-ray production cross sections and K..beta../K..cap alpha.. ratios are presented for 0.6- to 2.4-MeV protons and alpha particles incident on thin targets of selected elements from Nb to Gd. The K..beta../K..cap alpha.. ratios are compared to the theoretical predictions of Scofield and agree within 10%. The experimental cross sections are compared to the theoretical predictions of the plane-wave Born approximation (PWBA) and the PWBA modified to include binding energy, Coulomb deflection, and relativistic effects. It is seen that the PWBA modified for binding energy and Coulomb deflection effects agrees with the experimental data for Nb to within uncertainties, but its predictions are lower than the data by larger amounts as the target Z increases. Inclusion of an ad hoc semiclassical relativistic correction to the theoretical cross section, as suggested by Hansen, improves the agreement with the data, but overestimates the data for the highest-Z elements.
Variations common to the interplanetary magnetic field, the zonal atmospheric circulation and the earth's rotation
A study of the cyclic fluctuations in the earth's rotation, the geomagnetic field, the global atmospheric circulation and solar activity reveals the existence of 50-day and 120-day oscillations common to all. Our results, as well as the results obtained by radiometric measurements from the satellites Nimbus-7 and the Solar Maximum Mission (Wilson 1982; Pap 1985), suggest that their origin lies in the physical processes in the sun. The mechanism remains unexplained but from this work it follows that the role of the interplanetary magnetic field could very well be important.