The Delicate Violet Glow of High Voltage Corona DischargeErmia FirouzabadiAward: Top 100
School: queensland academy for science mathematics and technology When you think of electricity, you might picture bright sparks or lightning bolts, but electricity can also reveal itself as a delicate violet glow known as corona discharge. I was curious to see what this effect would look like on a very small scale, so I set up a simple experiment by placing a micro drill bit, just 0.8 mm wide, below two glass plates. I filled the gap between the glass panes with an electrolyte solution and applied a high voltage of 8 kV to this liquid layer. Since electric fields become especially concentrated around sharp edges and points, the tiny helical ridges of the drill bit created intense local electric fields, strong enough to ionize the surrounding air. This ionization released electrons from nitrogen molecules, and these electrons accelerated rapidly in the strong electric field, colliding with other nitrogen molecules and releasing even more electrons in an electron avalanche. Eventually, electrons recombined with positive nitrogen ions, causing the electrons to relax back down to lower energy states. This relaxation emitted photons of visible light, producing the soft purple glow characteristic of corona discharge. By photographing this effect with a 15-second exposure, I was able to capture intricate patterns of softly glowing plasma winding gently along the drill bit's edges. Capturing this subtle electrical glow up close made me appreciate how even simple setups can reveal interesting and beautiful physics hidden in plain sight. 
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