强流电子束碰撞电离背景气体研究

利用数值计算与粒子模拟两种方法，结合实际的实验数据，对高功率微波二极管中相对论电子束与背景气体相互作用碰撞产生的等离子体密度进行了研究.研究结果表明：碰撞产生的等离子体密度数值计算结果与粒子模拟结果基本一致，背景气压在0.01 Pa—0.05 Pa时，碰撞产生的等离子体密度在4—12×10⁹cm^-3，即便在考虑电子离子复合的情况下，数值计算结果与粒子模拟结果依然符合得很好.另外，粒子模拟结果表明：随着气压的增加，等离子体密度呈现先增大再减小然后又逐渐增大的过程，关键词：相对论电子束等离子体数值计算粒子模拟

Ionization of background gas by an intense relativistic electron beam

In the paper, the interaction of an intense relativistic electron beam with the background gas in the high power microwave diode is studied. According to the experimental data, the plasma density generated by impact ionization have been calculated using the numerical methode and particle-in-cell code. The results show that the values of the plasma density produced by impact ionization obtained by the two calculating methods agree well. The ionized plasma densities are 4－12×10⁹cm^-3 at the pressures of 0.01 Pa—0.05 Pa. Even considering the two- and three-body recombination effects, the values of the plasma densities produced by impact ionization obtained by the numerical methode and particle-in-cell code still agree well. In addition, the results of PIC simulation show that there is a hump in the plasma density curve with the increasing of pressure. Different from the simple numerical calculation, in calculating the plasma densities, the experimental data are used. The results obtained by the two calculation methodes using the experimental data will be very useful for high power microwave diode and microwave devices.