Acknowledgements

This work was performed under the auspices of the United States Department of Energy. LANL personnel who also made significant contributions include A Jacobson, M Pongratz, X M Shao, M Carter, D Roussel-Dupré, and R Sheldon. We thank the many hosts of LANL sferic array stations, without whom this research would not be possible. M Heavner acknowledges many fruitful discussions with C Talus.