We propose a method for the detection of a dynamical Casimir effect. Assuming that the Casimir photons are being generated in an electromagnetic cavity with a vibrating wall (dynamical Casimir...

The possibility of channeling low-energy relativistic positrons in some ionic crystals with axial symmetry is shown. The annihilation processes of positrons with medium electrons are investigated in detail. The lifetime of a positron in the regime of channeling is estimated; the existence of a long relaxation lifetime has been shown.

An analytical expression is received for the effective interaction potential of a fast charged particle with the ionic crystal CsCl near the direction of axis ⟨100⟩ as a function of the temperature of the medium. By numerical analysis it is shown that the effective potential of axial channeling of positrons along the axis ⟨100⟩ of negatively charged Cl⁻ ions practically doesn't depend on temperature of the media. The wavefunction and the energy spectrum of the localized state are investigated, and the possibility is proved for the formation of metastable, two-dimensional relativistic positron systems or the positron atoms (PA), i.e. the bound state of a positron in the present case with a negatively charged axis of ions. The problem of one-photon decay of PA is investigated. The possibilities of stimulation of resonant transitions between quantum states of PA by the external hypersound are investigated in detail.

We calculate the gain in a plane wiggler (undulator) with inhomogeneous magnetic field and in the external electromagnetic wave. The electromagnetic field-induced corrections to electron trajectories are found. The linear (field-independent) gain is calculated using these corrections to complex motion of electrons, which was described in previous paper, without electromagnetic field. This complex motion arises because of magnetic field inhomogeneity. It is shown that the account of inhomogeneity of the magnetic field leads to appearance of additional peaks in the gain of usual wiggler with uniform magnetic field.