School of Science and Engineering, Reykjavik University, Menntavegi 1, 101 Reykjavík, Iceland.
Phys Rev Lett. 2010 Apr 30;104(17):175002. doi: 10.1103/PhysRevLett.104.175002. Epub 2010 Apr 27.
We investigate the dynamics of a space-charge limited, photoinjected, electron beam in a microscopic vacuum diode. Because of the small nature of the system it is possible to conduct high-resolution simulations where the number of simulated particles is equal to the number of electrons within the system. In a series of simulations of molecular dynamics type, where electrons are treated as point charges, we address and analyze space-charge effects in a micrometer-scale vacuum diode. We have been able to reproduce breakup of a single pulse injected with a current density beyond the Child-Langmuir limit, and we find that continuous injection of current into the diode gap results in a well-defined train of electron bunches corresponding to THz frequency. A simple analytical explanation of this behavior is given.
我们研究了在微观真空二极管中，受空间电荷限制的光注入电子束的动力学。由于系统的微小性质，我们可以进行高分辨率的模拟，其中模拟粒子的数量等于系统内的电子数量。在一系列分子动力学类型的模拟中，我们将电子视为点电荷，解决并分析了在微尺度真空二极管中的空间电荷效应。我们已经能够重现超过 Child-Langmuir 极限的电流密度注入的单个脉冲的破裂，并且我们发现连续向二极管间隙注入电流会导致与太赫兹频率对应的电子束簇的清晰定义。对此行为给出了一个简单的分析解释。
