Basic Researches on Development of Plasma Accelerator

在弱磁化、不均匀的等离子体中(&lt；omega_0&gt；&lt；[]-&gt；omega_p&gt；&gt；&lt；omega_c&gt；：&lt；omega_o&gt；是入射电磁波的频率。电子回旋频率)，在静磁场B上传播的大幅度静电波在(-e)VpxB方向上加速电子(VpxB加速机制)。本研究旨在阐明VpxB加速机制是否适用于高能粒子加速器方案，以加速电子或离子。为此，(1)我们进行了弱磁化非均匀等离子体中微波等离子体相互作用的实验，(2)提出了实现粒子加速器的基本思路。当我们使用频率为2.86 GHz、最大功率为11KW的中等功率微波时，通过VpxB加速机制观察到了最大能量约为1keV的超热电子。此外，在共振吸收层附近还观察到了几个100 eV的电子，这些电子也是在垂直于波传播方向和静磁场的方向上发射的。这一过程也是由于波被困在密度腔中而产生的VpxB加速。利用慢波结构和VpxB加速方案的概念进行了实现高能粒子加速器的设计研究。结果表明，在相对论情况下，本文的加速器方案比传统的直线加速器效率更高。

In a weakly magnetized, inhomogeneous plasma ( <omega_0> <[]-> <omega_p> >> <omega_c> : <omega_o> is a frequency of an incident electromagnetic wave, <omega_p> the electron plasma frequency, and <omega_c> the electron cyclotron frequency), a large amplitude electrostatic wave propagating across the static magnetic field B accelerates electrons in the direction (-e)VpxB (VpxB acceleration mechanism). In the present research, it is aimed to clarify whether the VpxB acceleration mechanism is spplicable or not to the high energy particle accelrator scheme in order to accelerate electrons or ions. For those purposes, (1) we have performed the experiments on the microwave plasma interaction in a weakly magnetized inhomogeneous plasma, and (2) the basic ideas to realize a particle accelerator are proposed.When we applied the medium power microwave with frequency of 2.86 GHz and a maximum power 11 KW, hot electrons with maximum energy up to about 1 KeV have been observed through the process of VpxB acceleration mechanism. In addition, electrons with several 100 eV, which are also ejected in the direction perpendicular to both a wave propagation direction and the static magnetic field, are observed near the resonance absorption layer. This process is also expected to be the VpxB acceleration due to the wave trapped in the density cavity.Design studies are performed for realizing a high energy particle accelerator with the use of the slow wave structure and the concept of the VpxB acceleration scheme. It is clarified that in the relativistic case the present accelerator scheme is more efficient than the conventional linear accelerator.