Study on gas spark discharge plasma diagnosed by laser interferometric technology

Laser interferometric technology is an important means for diagnosing plasmas due to its high temporal and spatial resolution. In this work, air switch discharge plasma was diagnosed by a Mach-Zehnder laser interferometer with wavelength of 532 nm. The generated between two needle-type Cu electrodes. Three dimensional electron density profiles the were deduced numerical processing interferograms containing phase information obtained from experiments, revealing formation evolution processes arc channel At start discharge, large number electrons at cathode, then accelerated anode under action electric field. During motion, neutral gas ionized, cylindrical formed rapidly. A pressure gradient dense in channel, so began expand push surrounding air, forming shock wave. experimental results indicated that effective way study plasmas.