4 research outputs found
On features of the radiation from an electron moving along a helix inside a cylindrical hole in a homogeneous dielectric
The radiation from a charge moving along a helical trajectory inside a
cylindrical hole in homogeneous dielectric medium is investigated. Prompted by
availability of materials with large dielectric permittivity and
small absorption, we discuss the features of this type of radiation for media
with . It is shown that there are high peaks in the angular
distribution of radiation intensity at well-defined harmonics. The conditions
are specified for the cavity-to-helix radii ratio, , under
which the angle-integrated radiation intensity on some harmonics exceeds that
in the empty space. Though the amplification of radiation intensity increases
with increasing , the corresponding "resonant" values of ratio are practically independent of the dielectric permittivity
of surrounding medium. It is shown that an analogous amplification of radiation
takes place essentially for the same values of also for the
radiation in a cylindrical waveguide with conducting walls. An explanation of
this phenomenon is given.Comment: 8 pages, 6 figures, talk presented at RREPS07, 24-28 September, 2007,
Prague, Czech Republi