Electromagnetic separation applications

With a technique known as electromagnetic separation, applications of mass spectrometry began to spread away from the previous academic work into more practical fields like nuclear isotope enrichment. Mass spectrometers have been engaged on a preparative scale (calutrons), notably in the United States where in 1943 several kg of destined for the manufacture of the first atomic bombs were isolated (the Manhattan Project). This, now dated, procedure, which has a low flow rate of under 10 Pa, is still occasionally in use by other countries. 

The present chapter is devoted mainly to one of these new theories, in particular to its possible applications to photon physics and optics. This theory is based on the hypothesis of a nonzero divergence of the electric field in vacuo, in combination with the condition of Lorentz invariance. The nonzero electric field divergence, with an associated space-charge current density, introduces an extra degree of freedom that leads to new possible states of the electromagnetic field. This concept originated from some ideas by the author in the late 1960s, the first of which was published in a series of separate papers [10,12], and later in more complete forms and in reviews [13-20]. 

One can see that the full Hamiltonian consists of three terms, two which describe separately the parts for the atom and the field, and one which represents a coupling between the field (vector potential A) and terms from the atom (operator V,-). Obviously, it is this mixed term which is responsible for the photon-atom interaction. Provided perturbation theory can be applied, this term then acts as a transition operator between undisturbed initial and final states of the atom. Following this approach, one has to verify whether the disturbance caused by the electromagnetic field in the atom is small enough such that perturbation theory is applicable. Hence, one has to compare the terms which contain the vector potential A with an energy ch that is characteristic for the atomic Hamiltonian ... 

We will formulate the boundary conditions for practical applications of critical importance, namely those in which a smooth surface separates two media, 1 and 2, whose parameters are either constant or vary from point to point very slowly, so that in a small neighborhood of any point on the interface, the interface can be regarded as plane and the medium parameters can be constant. The derivation of these boundary conditions can be found in the textbooks on electromagnetic theory (see, for example, Stratton, 1941 Zhdanov and Keller, 1994 Kong, 2000). 

In geophysical applications, it is important to incorporate different types of sources in electromagnetic modeling. The most convenient way to do this is based on the separation of the field into the background (normal) and anomalous parts, considered in Chapter 9 ... 

Andersen, T., S<)rensen, G., in Electromagnetic isotope separators and their applications. Koch, J., Nielsen, K. O. (eds.). Amsterdam North-Holland 1965... 

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