摘要:
通过对层流平衡相对论电子的运动微分方程组进行数值求解,得到正则角动最在P_θ=0,p_θ=const.和P_θ∝r~2三种情况下,束流的传输特性.针对p_θ=0的相对论实心电子束,利用数值求解得到了与解析方法一致的结果,从而验证了数值方法的合理性;针对无法用解析方法求解的p_θ=O环行电子束、P_θ=const.和P_θ∝r~2的情况,利用数值方法得到了束流和空间极限电流关于波导、电子束结构和二极管电压等参数的变化规律及对轴向导引磁场的要求.计算结果表明:当相对论电子束以层流平衡态传输时,环行束较实心束具有更高的空间极限电流和更低的轴向导引磁场,且当阴极发射面与导引磁场的磁场线垂直时,维持电子束层流平衡所需的轴向导引磁场最低;电子束在有限磁场导引下以层流平衡态传输时,空间极限电流明显大于无限大磁场导引下一维近似的情况.利用数值方法对层流平衡相对论电子束进行理论研究,更全面地揭示了电子束在正则角动量满足不同条件时的束流特性,为设计新型结构的高功率微波器件提供理论参考.
Abstract:
A numerical solution for the self-consistent differential equations describing the laminar-flow equilibrium in magnetically focused relativistic electron beams is given and proved to be available by comparison with analytical results of solid electron beam in the case of p_θ=0(magnetically shielded sources).With the numerical method,the space-charge limited current and the externally applied magnetic field of both solid and annular electron beam in three cases of p_θ=0,P_θ=const and p_θ∝r~2(magnetically immerged sources)are presented and compared.It is shown that the conditions at the source with respect to the canonical angular momentum P_θ have little effect on the space-charge limited current and the xternally applied magnetic field,but more intense annular electron beam generated by the source with P_θ=const.can be transported in the same drift tube under lower guided magnetic field than solid ones.
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