Here’s what’s actually happening: This acrylic block is placed under a particle accelerator–generated electron beam. High-energy electrons are injected deep into the material. Acrylic (PMMA) is an excellent electrical insulator, meaning electrons can’t easily move through it. So instead of flowing out, the electrons get trapped inside the polymer matrix, building up an enormous internal electric field. Think of it like charging a battery with no wires attached. Over time, the trapped charge density becomes extreme. When the surface is mechanically stressed (like a sharp tap with a nail), the electric field concentrates at that point. If the local electric field exceeds the material’s dielectric strength (the maximum field an insulator can withstand before breaking down), something dramatic happens: ➡️ The acrylic locally undergoes dielectric breakdown ➡️ It momentarily behaves like a conductor ➡️ The trapped electrons discharge in a rapid avalanche ➡️ Branching plasma channels car...