Energy enhancement and spectrum narrowing in terahertz electron sources due to negative mass instability
Energy enhancement and spectrum narrowing in terahertz electron sources due to negative mass instability
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DOI：
10.1103/physrevaccelbeams.19.050704
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发表时间：
2016-05-26
影响因子：
1.7
通讯作者：
Savilov, A. V.
中科院分区：
文献类型：
--
作者：
Lurie, Yu.;Bratman, V. L.;Savilov, A. V.
对波导中相干自发波荡器辐射的模拟表明，使用负质量不稳定性（NMI）来保持激光驱动光注入器中形成的致密电子束的纵向尺寸，可以将太赫兹辐射源的功率能力提高许多倍。 NMI 是在波荡器中实现的，该波荡器具有由于电子的非等时纵向振荡而产生的组合螺旋和过共振均匀纵向磁场，其频率随着粒子能量的增加/减少而增加/减少。在这种条件下，即使在极高的电子密度下，也可以在长距离上保持束团的有效纵向尺寸。相应地，在窄频辐射光谱下能量提取效率超过 20%，这表明实现了紧凑而强大的太赫兹源。
Simulations of coherent spontaneous undulator radiation in a waveguide demonstrate that the use of negative mass instability (NMI) for retaining longitudinal sizes of dense electron bunches, which are formed in laser-driven photoinjectors, allows one to increase power capabilities of a terahertz radiation source by many times. The NMI is realized in an undulator with combined helical and over-resonance uniform longitudinal magnetic fields due to nonisochronous longitudinal oscillations of electrons, whose frequencies increase/decrease with increasing/decreasing particle energy. In such conditions, an effective longitudinal size of the bunches can be preserved at long distance even at an extremely high electron density. Correspondingly, an energy extraction efficiency of more than 20% is revealed at a narrow frequency radiation spectrum, suggesting realization of a compact and powerful THz source.