Purple Plasma

Lightning forms through the buildup of static electricity within thunderstorms, due to many ice and water collisions, and warm air mixing with cold air masses. This creates a separation of charge between the top of the clouds and bottom at the ground. When a threshold is reached, the atmosphere breaks down (i.e., becomes a plasma that allows electrons to freely travel), releasing a rapid, powerful electrical discharge, reaching temperatures greater than the plasma at the surface of the sun.  Lightning can sometimes appear purple or violet particularly at its edges or in its overall hue, especially in high humidity conditions.