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arXiv 1607.01503physics.acc-phphysics.class-ph
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圆柱形光栅旋转电荷的同步辐射和Smith-Purcell辐射

Synchrotron and Smith-Purcell radiations from a charge rotating around a cylindrical grating

A. A. Saharian, A. S. Kotanjyan, A. R. Mkrtchyan, B. V. Khachatryan

摘要:

本文研究了电荷绕圆柱对称导体旋转时的辐射。首先考虑了均匀介质中绕导电圆柱旋转的电荷问题。计算了圆柱表面的电荷和电流密度。导出了辐射强度的谱角密度公式。在第二部分中,我们研究了电荷绕平行于圆柱轴线的金属条圆柱面上的衍射光栅旋转时的辐射。光栅对辐射强度的影响近似于由旋转电荷场在条带上感生的表面电流。导出了电场和磁场的表达式以及给定谐波辐射强度的角密度的表达式。我们表明,同步加速器和史密斯-珀塞尔辐射之间的干扰可能会导致有趣的功能。特别是,大谐波上的辐射强度的行为可以从本质上不同于在真空中或围绕固体圆柱旋转的电荷。与这些极限情况不同,对于衍射光栅的几何形状,高次谐波上的辐射强度对于相对于圆柱轴的小角度不会消失。对于给定的装药特性,通过选择衍射光栅的参数,可以在装药旋转平面的法线附近具有高度定向的辐射。随着能量的降低,同步辐射的相对贡献减小,Smith-Purcell部分占主导地位。

英文摘要:

We investigate the radiation from a charge rotating around conductors with cylindrical symmetry. First the problem is considered with a charge rotating around a conducting cylinder immersed in a homogeneous medium. The surface charge and current densities induced on the cylinder surface are evaluated. A formula is derived for the spectral-angular density of the radiation intensity. In the second part, we study the radiation for a charge rotating around a diffraction grating on a cylindrical surface with metallic strips parallel to the cylinder axis. The effect of the grating on the radiation intensity is approximated by the surface currents induced on the strips by the field of the rotating charge. The expressions are derived for the electric and magnetic fields and for the angular density of the radiation intensity on a given harmonic. We show that the interference between the synchrotron and Smith-Purcell radiations may lead to interesting features. In particular, the behavior of the radiation intensity on large harmonics can be essentially different from that for a charge rotating in the vacuum or around a solid cylinder. Unlike to these limiting cases, for the geometry of diffraction grating the radiation intensity on higher harmonics does not vanish for small angles with respect to the cylinder axis. For given characteristics of the charge, by the choice of the parameters of the diffraction grating, one can have highly directional radiation near the normal to the plane of the charge rotation. With decreasing energy, the relative contribution of the synchrotron radiation decreases and the Smith-Purcell part is dominant.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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