Potential of a Cloud and Its Relationship to Charge Distribution on Stepped Leader and Dart Leader Channels

Abstract

The electric potential of a point in space in the vicinity of Earth can be easily defined by assuming the potential of Earth to be zero. The potential can be calculated by evaluating the line integral of the electrostatic field from a point on the ground to a point where the electrical potential is needed. The path of the integration is immaterial because the result is independent of the path of integration. This is because electrostatic fields are conservative. The potential of a metal object in the vicinity of the ground can be defined in the same way. In finding this potential it is possible to integrate the electric field from the ground to any point of the metal object along any path. This is because any point on the metal object has the same potential because, by definition, a metal contains free electrons that move along the surface of the metal and redistribute themselves until the potential at any point of the metal object is the same. But how does one define the potential of a cloud? One problem with the concept of cloud potential is that a cloud is just a collection of charges located on a nonconducting medium, which means that there is no specific definition for the potential of a cloud. The potential of a cloud may vary from one point to another. It may be very high close to the charge centers low at points far from them. Thus, when we speak about cloud potential in connection with a stepped leader, we actually mean the potential of the cloud near the region where the stepped leader was initiated.