高库仑量大电流两电极气体火花开关研究

设计了一个两电极气体火花开关，开关的主体部分仅包括阴极、阳极两个主电极，以及金属外壳和绝缘支撑外壳，两电极结构取消了触发极，消除了由于触发极烧蚀影响开关寿命的问题。开关设计工作电压23 kV，单脉冲能量1.2 MJ，峰值电流300 kA，单次脉冲电荷转移量110 C。初步试验阶段开关工作电压达到15 kV，开关的通流180 kA，电荷转移量为47.85 C。开关触发性能可靠，电极烧蚀均匀。

Influence of spherical aberration on beam parameters in design of laser optical focusing systems

Using the second-order-moment and entropy-based definitions of the beam width,changes of the beam parameters including beam width,far-field divergence angle and beam quality factor of flat-topped beams passing through a spherically aberrated lens are studied.It is shown that the spherical aberration affects the beam parameters in the image space.The relative errors of the beam width and far-field divergence angle introduced by the spherical aberration increase with increasing spherical aberration coefficient and decreasing beam order.The spherical aberration results in an increase of the beam quality factor of flat-topped beams.The relative errors of the waist width at the real focal plane depend on the sign of the spherical aberration coefficient,whereas the relative errors of the beam width at the geometrical focal plane are independent of the sign of spherical aberration coefficient.