Dynamics of Fast Electrical Breakdown in Electron-Charged Polymethyl Methacrylate

Dielectric materials in charged particle radiation environments have the tendency to trap and store the incident charges within their bulk, generating an electrostatic field inside the material. If the internal electric field increases beyond a given threshold due to continued charge accumulation or the introduction of a field-distorting defect, fast breakdown will occur. During the fast breakdown event, plasma channels rapidly form and grow throughout the solid insulation at velocities exceeding one million meters per second, redistributing the internal charge and causing permanent damage to the material. The experimental campaigns to investigate the breakdown channel propagation dynamics will be discussed, comparing both indirect and direct measurements. The experimental results are placed in the context of gaseous discharges in extreme density and pressure conditions, providing a possible explanation for the unusual dynamics observed in electron-charged solid materials.