Electrical conductivity of a metal powder struck by a spark

Equivalent resistance of a polydisperse powder layer struck by an electric spark is evaluated. Particles were computationally created and mixed using discrete element method; the mixing protocol homogenized particle size distribution within the sample. The conductivity was determined from the equivalent resistance network for the simulated powder bed. A plasma streamer attached to a particle on top of the sample. For each particle contact, an electrical breakdown was assumed; each individual contact resistance was calculated considering its geometry and plasma resistivity. Results of calculations compare well with the available experimental data.