We propose a scenario in which elevated ionic conductivity regions (EICRs) with dimensions of the order of 0.1–1 m are formed in the turbulent thundercloud environment. The starting point in this scenario is the occurrence of electron avalanches in the vicinity of colliding hydrometeors, leading to the formation of ion production centers. Their dimensions are of the order of \(1{0}^{-3}-1{0}^{-2}\) m, and their lifetime is of the order of \(1{0}^{-4}-1{0}^{-3}\) s. When a new ion production center is created inside the decimeter-scale residual ion concentration spot left behind by a previously established center, the local ion concentration steadily increases, which leads to the formation of decimeter-scale EICRs whose lifetime is measured in seconds. The relatively high conductivity of EICRs (up to \(1{0}^{-9}\) S/m or so) relative to the background conductivity (\(1{0}^{-14}\) S/m or less) ensures their polarization in external electric field within a few milliseconds or so. The EICR formation mechanism requires only one condition: the rate of occurrence of ion production centers per unit time in a unit volume should exceed the percolation-theory-based critical level of \(1{0}^{-1}\) m\({}^{-3}\) s\({}^{-1}\). Hydrometeor collision rates three and even four orders of magnitude higher than this value have been reported from observations. Presence of EICRs in the cloud provides local electric field enhancements and pre-ionization levels that will lead to the formation of additional ion production centers and may be sufficient for the initiation and development of streamers and, eventually, lightning.

我们提出了在湍动的雷云环境中形成尺寸约为0.1–1 m的升高的离子电导率区域（EICR）的方案。在这种情况下的起点是在碰撞的水凝物附近发生电子雪崩，从而导致离子产生中心的形成。它们的尺寸约为\（1 {0} ^ {-3} -1 {0} ^ {-2} \）  m，寿命约为\（1 {0} ^ {-4 } -1 {0} ^ {-3} \） s。当在以前建立的中心留下的分米级残留离子浓度点内创建新的离子产生中心时，局部离子浓度稳定增加，这导致形成分米级EICR，其寿命以秒为单位。 相对于背景电导率（\（1 {0} ^ {-14} \）  S / m而言，EICR的电导率相对较高（高达\（1 {0} ^ {-9 } \） S / m。 （或更少）以确保它们在几毫秒左右的时间内在外部电场中极化。EICR形成机理仅需满足以下一种条件：单位体积中每单位时间的离子产生中心的发生率应超过基于渗流理论的临界水平\（1 {0} ^ {-1} \）  m \ （{} ^ {-3} \） s \（{} ^ {-1} \）。据观察，水流星碰撞率比该值高三个甚至四个数量级。云中存在EICR会增强局部电场并提高电离前水平，这将导致形成更多的离子产生中心，并且可能足以引发和发展拖缆，并最终形成闪电。