Corona Discharge

Today I was leaving work late at usual and heard the most interesting thing. You know that great scene in the old Frankenstien movie when Dr. Frankenstien is going to use the power of electricity to reanimate the monster? All that sizzling snap and crackle as the monster's body went up into the castle tower? That is precisely the sound I heard.

A terrible, wet fog hung over the place. It was so loaded with water that you had to pull hard against it just to breathe. It was still, cold and heavy turning all the sodium lights into fuzzy gumball smears.


I followed my ears to the source of the sizzling arcs. A high tension electrical line, very high up on poles runs across the street from my building. The science of what I saw is pretty cool, but just seeing it happen was really something. An area around the lines would build up a blue and purple glow, then pop with a crackle and dim a little, but not be gone. Then another place would begin to glow.


This picture doesn't do any of it justice, but you kind of see how the pole and the line were glowing. It was supremely cool.

Here is what they say about the science of it:
The electric field contains enough electricity to ionize the air. Specifically, it will ionize oxygen and nitrogen in the air. This can produce a low energy plasma, the corona discharge. A plasma is a fourth state of matter (after solid, liquid, and gas). It is like a gas or liquid, but molecules are separated into atoms, and the outer electrons are stripped off and are freed into the plasma. In comparison, the sun is essentially a big ball of very hot plasma.

The current carried in the power line alternates direction, usually 60 times a second (60Hz). This propagates to the electrical field, affecting the plasma, and producing the audible vibration of air.

Will be back to the questions and answers soon.