Table of contents

A model for the generation of an ion flow in a vacuum arcs is proposed, based upon the analysis of electron processes. It is shown that the charge states and the velocities of directed motion of the ions result from cathode microsections being explosively destroyed by Joule heating with a high-density current. In this case, the ionization processes occur within a narrow (of the order of a micrometer) region near the cathode, and thereafter the ionic composition of the plasma remains unchanged. For arc currents of up to a kiloampere, a current increase simply increases the number of simultaneously operating ectons, thus explaining the weak experimental dependence of ion flow parameters on the vacuum arc current.

Theoretical ideas on the formation and evolution of charged particle tracks in a condensed medium are discussed. The historical development of the field is briefly reviewed. The distribution of charged particle energies over quantum states and the volume of the absorbing medium are considered, and conditions for the formation of various track structures (entities) are discussed. The structures of extended heavy-ion tracks are compared for some ion parameters and track characteristics under equal conditions. Relaxation processes in the tracks of multiply charged ions are analyzed. Track effects are considered and possible mechanisms for the formation of chemically active defects in a latent track are described.

Research into the phenomenon of dynamic self-organization and the excited ('anger') state of multidomain magnetic films with perpendicular anisotropy is reviewed. The phenomenon was dicsovered in 1988 when studying the domain structure of iron garnet films in low-frequency (0.1–10 kHz) ac magnetic fields.

Neural network models are discussed that have been developed during the last decade with the purpose of reproducing spatio-temporal patterns of neural activity in different brain structures. The main goal of the modeling was to test hypotheses of synchronization, temporal and phase relations in brain information processing. The models being considered are those of temporal structure of spike sequences, of neural activity dynamics, and oscillatory models of attention and feature integration.

The formulation of Fermat's principle for electromagnetic waves traveling in materials with a negative refractive index is refined. It is shown that a formulation in terms of the minimum (or extremum) of wave travel time between two points is not correct in general. The correct formulation involves the extremum of the total optical length, with the optical length for the wave propagation through left-handed materials taken to be negative.