Cherenkov Radiation from a Hollow Conical Targets: Off-Axis Charge Motion

TL;DR

This paper investigates how a shifted charge trajectory in a hollow conical dielectric target affects Cherenkov radiation patterns, revealing an asymmetric 'Cherenkov spotlight' effect that can be enhanced by tuning target parameters and charge velocity.

Contribution

It introduces the analysis of off-axis charge motion in conical targets, demonstrating asymmetric Cherenkov radiation and the conditions for the Cherenkov spotlight effect.

Findings

Asymmetric CR patterns due to charge shift

Enhanced CR intensity in the Cherenkov spotlight regime

Charge speed variation influences the CR distribution

Abstract

Cherenkov radiation (CR) generated by a charge moving through a hollow conical target made of dielectric material is analyzed. We consider two cases: the charge moves from the base of the cone to its top (``straight'' cone) or from the top to the base (``inverted'' cone). Unlike previous papers, a nonzero shift of the charge trajectory from the symmetry axis is taken into account which leads to generation of asymmetric CR. The most interesting effect is the phenomenon of ``Cherenkov spotlight'' which has been reported earlier for axially symmetric problems. This effect allows essential enhancement of the CR intensity in the far-field region by proper selection of the target's parameters and charge velocity. Here we describe the influence of charge shift on CR far-field patterns paying the main attention to the ``Cherenkov spotlight'' regime. Influence of variation of the charge speed on this phenomenon is also investigated.