Breakdown of metals subject to intense electric fields is a long-standing limiting factor in high-voltage applications. The mechanism leading to breakdown nucleation is not completely understood. Previously, it was suggested that breakdown can be nucleated by a critical transition in the population of mobile dislocations near the surface of electrodes. This was formulated in terms of a mean-field mobile dislocation density fluctuation (MDDF) model. Based on this model, it was proposed that prebreakdown fluctuations of the mobile dislocation density might be observed as spikes in the dark current between the electrodes. We constructed a setup in which these fluctuations were measured. The rate of fluctuations, as a function of the electric field between the electrodes, agrees with the predictions of the MDDF model, both in functional form and in absolute numerical rates. This numerical agreement was obtained using previously derived numerical parameters of the model. In addition, for each electric field, the distribution of times between current fluctuations was examined. The results indicate that each such prebreakdown fluctuation is the result of a two-step process. This characteristic, too, is in line with the MDDF model, which predicts that a characteristic prebreakdown current event is described as two separate steps in a Markov process, occurring in quick succession.

中文翻译：

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暗电流尖峰可作为强直流电场下移动位错动力学的指标

金属在强电场中的击穿是高压应用中长期存在的限制因素。导致击穿形核的机理尚不完全清楚。以前，有人提出击穿可以通过电极表面附近的移动位错的临界转变来形核。这是根据平均场移动位错密度波动（MDDF）模型制定的。基于该模型，提出了可移动位错密度的预击穿波动可能被观察为电极之间暗电流的尖峰。我们构建了一个可以测量这些波动的设置。作为电极之间电场的函数的波动率与MDDF模型的预测一致，无论是函数形式还是绝对数值率。使用先前导出的模型数值参数获得此数值一致性。另外，对于每个电场，检查电流波动之间的时间分布。结果表明，每个这样的预分解波动都是两步过程的结果。该特征也与MDDF模型一致，该模型预测，特征性的击穿前电流事件被描述为快速连续发生的马尔可夫过程中的两个独立步骤。结果表明，每个这样的预分解波动都是两步过程的结果。该特征也与MDDF模型一致，该模型预测，特征性的击穿前电流事件被描述为快速连续发生的马尔可夫过程中的两个独立步骤。结果表明，每个这样的预分解波动都是两步过程的结果。该特征也与MDDF模型一致，该模型预测，特征性的击穿前电流事件被描述为快速连续发生的马尔可夫过程中的两个独立步骤。