基于自持电中性闪电放电参数化模型研究云闪通道中沉积电荷的变化特征

Research on variation characteristics of deposited charge in intracloud lightning channel based on Self-Sustained Charge Neutrality Intracloud Lightning Parameterization

中文关键词:  雷电物理学,闪电参数化,通道电荷,云闪起始点,再击穿过程

英文关键词:Lightning physics, Lightning parameterization, Channel charge, Initial point of intracloud lightning, Re-breakdown process

中文摘要:

      【目的】闪电通道的电荷特征是雷电物理研究的重点,而现有的观测手段难以直接获取通道中电荷的详细演变特征,为了深入研究闪电通道电荷的变化特征并与观测形成互补,开展模式工作必不可少。【资料和方法】利用自持电中性闪电放电参数化模型,在三极电荷背景下模拟多次云闪并从中选取一次典型个例,分析该云闪通道内电荷的变化特征及其影响因素,【结果】结果如下:正、负先导通道形成时,通道内会沉积一定量的正、负极性的初始电荷；后继分支延伸时,之前的通道会沉积来自后继分支的异极性电荷,通道内初始极性的电荷会不断被中和,部分通道的电荷极性会发生变化；通道熄灭或后继分支停止延伸时,通道内电荷不再变化；再击穿过程发生时,截止通道内的异极性电荷会显著减少,再次激活的通道内的异极性电荷会显著增多。【结论】研究表明:先导通道内的电荷变化与通道自身的状态以及后继分支的延伸状况有关；通道电荷变化幅度与通道初始电荷量以及后继分支的活跃程度呈正相关,而通道的初始电荷量与通道首次击穿电场呈正相关。此外,在正、负先导极性不对称性的影响下,云闪起始点更倾向于沉积正电荷。

英文摘要:

      The characteristics of charge in lightning channel are the focus of lightning physics research, but it is difficult for existing observation methods to directly obtain the detailed evolution characteristics of charge in the channel. In order to further study the variation characteristics of charge in lightning channel and complement developing lightning detection technology, it is necessary to carry out model work. Using the Self-Sustained Charge Neutrality Intracloud Lightning Parameterization model, multiple intracloud flashes are simulated under the three-pole charge background and a typical case is selected. The variation characteristics of channel charge and their influencing factors are analyzed. The results are as follows: A certain amount of positive or negative polarity initial charge will deposit in the channels when these leader channels first form; When the subsequent branch extends, the previous channel will deposit heteropolar charges from the subsequent branches, and the charge of the initial polarity in the channel will be continuously neutralized, the polarity of some channels may change; The charge in the channel will not change if the channel has decayed or its subsequent branches stop extending. When the re-breakdown process occurs, the heteropolar charge in the cut-off channel will be significantly reduced, the heteropolar charge in the reactivated channel will be significantly increased. The research shows that: The charge variation in the leader channel is related to the state of the channel itself and the extension of the subsequent branches. The amplitude of charge change in the channel is positively correlated with the initial charge and the activity of subsequent branches, and the initial charge is positively correlated with the first breakdown electric field. In addition, under the influence of polarity asymmetry between positive and negative leaders, the initial point of intracloud lightning tend to deposit more positive charges.