Development of Electron Linear Accelerator based on the VpxB Acceleration Scheme

本课题的主要任务是研制一台等离子体基电子直线加速器，用高功率、短脉冲微波激发大振幅电子等离子体波。具体地说，“VpxB加速方案”，这是在我们的实验室发现，除了大振幅等离子体波尾场激发的短微波脉冲，应采用。这一方案的提出是建立在等离子体中存在的各种非线性现象的基础上的，而这些现象也是需要深入研究的，近两年来，我们朝着研制等离子体电子直线加速器的目标迈出了第一步。然而，我们面临着严重的技术问题，迫切需要突破。也就是说，需要超短、高功率的微波脉冲。典型的规格如下：1 nsec FWHM，50-100 kW峰值功率（f= 2.86 GHz）或0.5 nsec FWHM，250-500 kW峰值功率（f = 9.5 GHz）。这个系统的基本思想现在正在我们的实验室里发展，我们仍然需要很多时间用于实验。这是今后几年的关键问题之一，我们已经发现了新的现象，如大振幅（Δ n/n（）SY ≥ 0）。[）40%）离子波的激发和等离子体波回波的观测，这是自1967年首次理论预言以来25年来一直期待的。我们研制了基于VpxB方案的真空电子直线加速器，旨在发展紧凑、高效、高加速梯度的加速器。延迟电路采用圆盘形电极产生的纵模电磁波。垂直静磁场用于制作VpxB方案。在上述新方案中，我们已经成功地加速了电子。

The primary task of the present investigation is to develop a plasma based electron linear accelerator, by exciting large amplitude electron plasma wave with high power, short pulse microwave. Specifically, the "VpxB acceleration scheme", which was found experimentally in our laboratory, should be employed, in addition to the large amplitude plasma wave wake field excited by the short microwave pulse. The above mentioned scheme should base on the variety of nonlinear phenomena occurring in the plasma, which also have to be investigated intensively.Last two years, we stepped out the first step toward the goal of developing the plasma based electron linear accelerator. We, however, have faced to serious technical problem which should be broken through very urgently. That is, the ultra-short, high power microwave pulse is required. The typical specifications follow, 1 nsec FWHM with 50-100 kW peak power at f= 2.86 GHz or 0.5 nsec FWHM 250-500 kW peak power at f = 9.5 GHz. The basic idea for this system is now under development in our laboratory, still we need much time for use in the experiments. This is one of the key issues for the next several years.We have found new phenomena such as large amplitude (deltan/n (] SY.gtoreq.[) 40 %) ion wave excitation by a short microwave pulse with typical pulse width of 70 nsec or less and an observation of temporal plasma wave echoes which has been expected for last 25 years after the first theoretical prediction in 1967.We have developed electron linear accelerators based on the VpxB scheme in vacuum for aiming to develop the compact, high efficiency, high acceleration gradient accelerators. We employed the longitudinal mode electro-magnetic wave produced by the disk shaped electrode for the delay circuit. The vertical static magnetic field is applied for making the VpxB scheme. We have succeeded to accelerate electrons in the above mentioned new scheme.