12,978 research outputs found
On the problem of relativistic particles motion in strong magnetic field and dense matter
We consider a problem of electron motion in different media and magnetic
field. It is shown that in case of nonmoving medium and constant homogenious
magnetic field the electron energies are quantized. We also discuss the general
problem of eigenvectors and eigenvalues of a given class of Hamiltonians. We
examine obtained exact solutions for the particular case of the electron motion
in a rotating neutron star with account for matter and magnetic field effects.
We argue that all of these considerations can be usefull for astrophysical
applications
Species Distribution Patterns in Subgenus Cuspidata (Genus Sphagnum L.) on the East European Plain and Eastern Fennoscandia
The geographic range of 13 species from the subgenus Cuspidata in the East European Plain and Eastern Fennoscandia has been studied. Model maps for each species occurrence were constructed using geostatistics techniques (kriging method). Continuous coverages of 23 climatic factors were used in analysis also. We used dataset that proposed by authors of program WORLDCLIM. To learn how corresponding values of climatic factors and species occurrence correlation and cluster analysis were conducted. It was found that 7 of 13 species are widespread on the East European Plain and Eastern Fennoscandia, and 6 species have the restricted ranges. Values of occurrence of all species (except Sphagnum lenense) have a strong correlation with moisture factors (relative air humidity and sum of precipitation) in summer-autumn period. Such preferences allow them to grow successfully in Subarctic and Baltic regions, where high climatic humidity is observed. Restricted species are concentrated around the Baltic Sea and zones of the highest occurrence of widespread species are located at the same region. All species can be divided into four clusters according to its climatic preferences. Distribution of such species as S. obtusum seems to be strongly associated with two tongues of the Last Glacier, and this species seems to be a glacial relic
The experimental study of the surface current excitation under the influence of a relativistic electron electromagnetic field
The problem of the surface current excitation in a conductive targets by a
relativistic electron electric field as the origin of such radiation mechanisms
as diffraction and transition radiation of relativistic electron was considered
in frame of both surface current and pseudo-photon methods. The contradiction
between these viewpoints in respect to the surface current on the target
downstream surface necessitated the experimental test of this phenomenon. The
test performed on electron beam of the 6 MeV microtron showed, that not any
surface current is induced on the target downstream surface under the influence
of a relativistic electron electromagnetic field in contrast to the upstream
surface. This is important implication for the understanding of the forward
transition and diffraction radiation nature.Comment: Was Presented at the symposium Channeling 2008 (Charged and Neutral
Particles Channeling Phenomena), October 25 - November 1, 2008 Erice (Trapani
- Sicily), Italy, and was accepted for publication in proceedings of
symposiu
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