The physical mechanism of leader formation and development is not well understood. In this study, we present experimental and simulation results obtained with a 10 m long air gap discharge. A 10 m outdoor discharge experiment is carried out to obtain the current, voltage, and optical image during the leader discharge process. Four different impulse voltages were applied to the rod-plane gap. The measured current is used as an input for a plasma model, then the temperature and electric field could be calculated. The simulation results show that the temperature of the streamer stem during the dark period may exceed 2000 K. In addition, the critical charge required for leader initiation can be as low as 0.27 μC for a 10 m air gap. The channel temperature is relatively stable in the process of leader development, which is maintained at about 4500 K. The electron density is about 0.5–3 × 10²⁰ m⁻³, and the discharge channel conductivity fluctuates in the range of 1–10 S/m for the leader current between 1 and 2 A. A long dark period is tended to be associated with a higher injected charge by the first streamer. It is inferred that the voltage increments during the dark period play an important role in promoting streamer-to-leader transition, except for temperature and the injected charge.

中文翻译：

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10 m长气隙下先导产生和发展的放电​​特性——实验观察与模拟结果

领导者形成和发展的物理机制尚不清楚。在这项研究中，我们展示了通过 10 m 长的气隙放电获得的实验和模拟结果。进行10 m户外放电实验，获取先导放电过程中的电流、电压和光学图像。四种不同的脉冲电压被施加到杆平面间隙。测量的电流用作等离子体模型的输入，然后可以计算温度和电场。模拟结果表明，暗期流注杆的温度可能超过2000 K。此外，对于10 m的气隙，先导启动所需的临界电荷可以低至0.27 μC。先导发展过程中沟道温度相对稳定，维持在4500 K左右。电子密度约为0.5~3 × 10 20 ^m  −3 ^，放电沟道电导率在1~10 S范围内波动。 /m 对于 1 到 2 A 之间的先导电流。较长的暗期往往与第一个流注的较高注入电荷相关。据推测，除了温度和注入电荷之外，暗期期间的电压增量在促进流注到先导转变中起着重要作用。