967 research outputs found
Solar cosmic rays in October-November 2003 and the particle acceleration by shocks in interplanetary medium in the October 28, 2003 event
Synchronous manifestations of 160-min pulsations in the atmospheric pressure at widely separated stations
Goldstone mode of Skyrmion Crystal
We discuss the Goldstone mode of skyrmion crystal in a model of
two-dimenssional ferromagnet with Dzyaloshinskii-Moriya interaction in magnetic
field. We use stereographic projection approach to construct skyrmion crystal
and consider skyrmion's displacement field. The small overlap of the individual
skyrmion images restricts the potential energy to the interaction of nearest
neighboring displacements. The closed form of the Goldstone mode dispersion is
found and its dependence on the magnetic field is studied. We use semiclassical
quantization to define the Green's function and show that the propagation of
displacements through the crystal changes its tensorial form from isotropic to
anisotropic one at large distances.Comment: 6 pages, 4 figure
Generation of powerful terahertz emission in a beam-driven strong plasma turbulence
Generation of terahertz electromagnetic radiation due to coalescence of
upper-hybrid waves in the long-wavelength region of strong plasma turbulence
driven by a high-current relativistic electron beam in a magnetized plasma is
investigated. The width of frequency spectrum as well as angular
characteristics of this radiation for various values of plasma density and
turbulence energy are calculated using the simple theoretical model adequately
describing beam-plasma experiments at mirror traps. It is shown that the power
density of electromagnetic emission at the second harmonic of plasma frequency
in the terahertz range for these laboratory experiments can reach the level of
1 with 1% conversion efficiency of beam energy losses to
electromagnetic emission
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