磁绝缘感应电压叠加器注入电流空间非均匀分布及影响因素分析

Spatially Asymmetric Distribution and Related Influence Factors of Injected Currents in Magnetically-Insulated Induction Voltage Adders

磁绝缘感应电压叠加器(MIVA)脉冲馈入方式导致感应腔注入电流空间非均匀分布,这对感应腔性能(如等效电感、电磁场分布、输出参数等)和MIVA次级磁绝缘特性(如电子鞘层、流阻抗、电流损失等)产生影响。建立MIVA感应腔全电磁模型,并得到典型结构下感应腔初级注入电流空间分布和次级磁场强度的分布特性。给出电流不均匀系数δ(t)的动态变化过程,仿真分析注入电流脉宽、感应腔初级绝缘介质、脉冲馈入路数及时间抖动等因素对δ(t)的影响规律。结果表明,δ(t)动态过程分为快速下降、稳定和缓慢下降三个阶段,注入电流脉宽影响稳定阶段持续时间和缓慢下降阶段;初级绝缘介质影响感应腔内电磁脉冲传播速率,进而对电流空间分布产生影响;注入脉冲路数对注入电流空间分布有决定性影响;双路脉冲馈入感应腔注入时间不同步时,不均匀系数发生改变。开展了单级感应腔注入电流空间分布实验,验证了电磁计算的正确性。

The special injection manner of magnetically-insulated induction voltage adders(MIVA)leads to the spatially asymmetric distributions of injected currents.It might affect the cavity performances and the characteristics of magnetic insulation in the secondary sides of MIVA,such as the electron sheath,flow impedance,and the current variations.In this paper,a full-size electromagnetic model of an induction cavity was developed,to acquire the spatial distribution of injected currents in the primary sides of cavities and the profiles of magnetic fields in the secondary sides.The dynamic process of the asymmetric coefficient,δ(t),was obtained.Some factors affecting theδ(t)were analyzed in detail,such as the pulse width of injected currents,the insulating medium in the primary sides of cavities,the number of injected pulses and their driver jitter.It is found that,the dynamic process of asymmetric coefficient,δ(t),consists of three phases,i.e.,the fast drop process,steady state,and slow decrease process.The pulse width of injected currents affects the duration of the steady state and the subsequent third process.The insulating medium in the primary sides of cavities affects the spatial distributions of injected currents by changing the transmission speed of electrical pulses in cavities.The number of injected pulses has crucial influence on the current distributions.As the two pulses driving the same cavity could not arrive simultaneously,the current distributions would change.Moreover,the current injection experiments of a single-stage cavity in part confirm the simulation results.