Distribution Characteristics and Shielding Effects of Ion Clouds.

The latest research shows that the ions generated by the corona discharge of lightning rod have dual functions of attracting and shielding lightning discharge. After the lightning rod is installed at a certain height on the ground, the lightning rod tip reaches the corona threshold to ionize the surrounding air and generate positive and negative ions under the action of the electric field at the end of the lightning downward leader. Constrained by Coulomb's Law, its positive ions (opposite charges attract each other) form an upward leader (streamer), which moves towards the end of the lightning downward leader and is connected to the downward leader, establishing a discharge channel to attract lightning to the needle tip and discharge the current to the ground, and playing a role in attracting lightning. Its negative ions are repelled by the electric field at the end of the lightning downward leader (repelled by isotropic charges) and influenced by the wind, and diffuse in the downwind area to form an ion cloud, inhibiting the growth of corona at the tip of ground objects, and playing a role in shielding lightning. In this paper, Franklin's understanding of the role of lightning rod and Yang Shaojie's new definition of the working principle of lightning rod are briefly introduced. The formation mechanism, distribution characteristics, shielding effect, and impact on lightning strike point distribution of ion clouds are analyzed. Additionally, the important role of shielding effects of ion clouds in regional lightning protection is introduced, which provides a theoretical basis for the correct understanding and use of lightning rod. [ABSTRACT FROM AUTHOR]