6 research outputs found
SURFACE ELECTROMAGNETIC WAVES IN A GAP BETWEEN TWO LEFT-HANDED MATERIALS
The slow surface electromagnetic waves that propagate along the planar waveguide structure that contains two identical isotropic left-handed material with the vacuum (or air) gap has been considered. The possibility of propagation of slow surface electromagnetic waves of TM and TE polarizations in the frequency range at which the dielectric permittivity and magnetic permeability are negative are shown. By selecting a frequency, one, two or three modes can be excited simultaneously. The group and phase velocities of the TE polarization waves are directed in opposite directions. The frequency range of the existence of the TE mode with an antisymmetric field distribution lies above the frequency range of the existence of the TE mode with a symmetric field distribution. The TM wave, depending on the wavelength, can be either forward or backward, or have zero group velocity. The wave of TM-polarization has a slightly varying group velocity in a sufficiently wide frequency range. A rich set of different properties of these waves make them promising in applications
Bunch-excited wakefield in dielectric waveguide with hollow plasma channel
Wakefield excitation by a single relativistic electron bunch in a
plasma-dielectric accelerating structure has been studied both analytically and
numerically. The structure represents a dielectric-loaded cylindrical metal
waveguide, which has partially plasma-filled channel (the hollow plasma
channel) to transport charged particles. Assuming the linear regime of
excitation, analytical expressions have been derived for the longitudinal and
radial wakefields generated by a finite-size electron bunch. Axial profiles of
wakefield component amplitudes have been studied, and their mode and spectrum
analyses have been performed. Furthermore, the electron bunch-driven wakefield
excitation has been PIC-simulated numerically for the quasi-linear regime. The
comparative analysis of the data resulting from analytical studies and the ones
obtained by numerical simulation has demonstrated qualitative agreement between
the results
Nonlinear theory of wakefield excitation in a rectangular multizone dielectric resonator
A nonlinear self-consistent theory has been constructed and used to investigate numerically the wakefield excitation in multilayered dielectric resonators by relativistic electron bunches. Analytical expressions for solenoidal and potential components of an excited electromagnetic field have been derived. The excitation of a five-zone dielectric resonator by relativistic electron bunches was numerically investigated and comparison was made between the longitudinal distribution of an axial electric field and the results obtained previously for a corresponding problem in the waveguide formulation. The necessity of optimizing geometrical parameters of the resonator to reduce mode amplitudes nonresonant with a bunch, and to obtain a symmetric distribution of the longitudinal electric field component in the drive and accelerating channels, has been demonstrated