AE24A-04:
Comparison of Simulations of Preliminary Breakdown to Observations from the Huntsville Alabama Marx Meter Array
Tuesday, 16 December 2014: 4:45 PM
Brant E Carlson, Carthage College, Kenosha, WI, United States, Can Liang, Stanford University, Brisbane, CA, United States, Phillip M Bitzer, UAHuntsville, Huntsville, AL, United States and Hugh J Christian Jr, University of Alabama in Huntsville, Huntsville, AL, United States
Abstract:
Preliminary breakdown pulses in electric field change records are thought to be produced by sudden extensions of the lightning channel. We present detailed time domain electrodynamic simulations of extension of an existing lightning leader channel due to heating processes and compare the results to observations of a natural cloud-to-ground lightning discharge made with the Huntsville Alabama Marx Meter Array (HAMMA) at a variety of locations near the discharge. Varying the geometry and parameters of the simulations in an attempt to reproduce the data allows us to constrain the directionality and physical properties of the channel. We simulate a variety of leader step phenomena, including uniform heating over the entire step, connection with a space leader, and dart leader propagation onto a preconditioned channel. Results support the notion of impulsive channel extension as the mechanism for preliminary breakdown and shed light on the mechanics of the process.
