Spark Discharge is a first-of-its-kind text, providing a comprehensive and systematic description of the spark breakdown of long gas gaps. It discusses the nature of a long spark, physical peculiarities of relevant gas discharge processes, methods and results of experimental studies, and analytical and numerical models. The most important applications in high-voltage engineering are covered in a single volume. The straightforward presentation of complicated materials, the deep insight into the nature of the processes, and the simplified mathematical descriptions of the phenomena, make Spark Discharge an excellent textbook for students and an indispensable reference for researchers, physicists, and engineers.1 The Concepts of Spark, Corona, and Breakdown Lightning and Long Spark Leaders Corona and Spark Discharges Avalanche and Streamer Mechanisms of Gas Breakdown What Is a Breakdown? 2 Basic Information on Processes in Ionized Gases Drift and Diffusion of Electrons and Ions Molecular Ionization and Excitation Electron Loss and Liberation Electron and Ion Gases in Electric Fields Breakdown by Avalanche Multiplcation Induced Charge and Circuit Current Strongly Ionized Equilibrium Plasma Equilibrium Plasma Arc with Current 3 Basic Processes in Spark Breakdown Streamer as an Ionization Wave Electrical Properties of a Plasma Channel Gas Temperature and Energy Balance Initial Ionization Mechanisms The Streamer Inception Is a Streamer Breakdown Possible? An Ionization Wave in Spark Breakdown 4 Experimental Techniques High Voltage Sources Voltage Measurement Current Measurement Current Data Analysis Gap Charge Measurement Electric Field Measurement Optical Registration of Discharge Synchronization Gap Field Data: Theory and Reality 5 Long Streamers Phenomenology and Dimensl&