[en] Exact solutions of the Schroedinger equation exist in the case of a linear oscillator submitted to a strong force exerted for a time much shorter than the oscillation period, and lead to transition probabilities admitting an enhancement (in suitable conditions) of the relative number of elastic processes with increasing perturbing energy. When, however, the oscillator is an atom belonging to a crystal lattice, elastic processes present new and interesting rigidity properties, which could be explored by means of slow neutron scattering and nano-technologies

[en] The weakly relativistic theory of absorption and emission of electron cyclotron waves in hot magnetized plasmas is developed for a large class of anisotropic electron distribution functions. The results are expressed in terms of the weakly relativistic plasma dispersion functions, and therefore of the well-known plasma Z-function. The particular case of a loss-cone electron distribution function is presented as a simple example. (author)

[en] The relativistic dispersion relation of electron Bernstein waves is treated, removing the ''classical'' divergences and cutoff at normal incidence. The pertinent quasilinear equations are obtained and discussed

[en] The dielectric tensor for a magnetoactive plasma is obtained for waves propagating perpendicularly to the external magnetic field. This case requires a relativistic treatment, avoiding the classical singularities. A new and simple approach is presented, allowing to minimize the calculations and hypotheses of the previous works on this topic. (author)

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[en] A peculiarity of the quasi-optical propagation of a Gaussian beam of electromagnetic waves is that it requires a treatment taking account, step by step, of all of its rays together. The dispersion relation from which such a ray-tracing may be deduced is, in fact, characterized not only by the medium where the beam is launched but also by the intrinsic beam structure. The behaviour of three-dimensional Gaussian beams in the electron-cyclotron frequency range is considered, with particular attention paid to their propagation in toroidal plasmas of fusion interest (with ITER-like parameters and various magnetic equilibrium configurations), to the generality of their launching conditions and to their power deposition profiles around resonant layers. (Author)

[en] The weakly relativistic dielectric tensor is obtained, for non-thermal plasmas where the electron distribution may be assumed to be a combination of suitable drifting Maxwellians. The relativistic dispersion functions are given (and turn out to be easily computable) both in their exact integral form and by an exact recurrence relation in terms of the classical Z function. These expressions are applied to study, solving the electromagnetic dispersion relation, the absorption properties, in the electron cyclotron range, of a warm plasma as a function of the streaming parameter

[en] The peculiar properties of the Moessbauer effect provide an important test, and possibly a challenge, to Quantum Physics. The zero-point momentum reservoir of the mechanical oscillators forming a crystal lattice is indicated, in the present paper, as the possible way out from apparent contradictions of the observed features with both momentum conservation and the uncertainty principle

No abstract available