Hi everybody!
Gee you're good!
I'm the guy on the picture of the bluish power lines!
Yes its a coronal effect or the other term is ionization and also known as St-Elmo's fire! (remember the movie : Moby dick!)
I live in James-Bay in the Canadian north, usually very dry!
That night, I wanted to try my new camera and do "Darth Vader" under the 735 000 V power lines with a 8 ft long fluorescent...yep they do light up by themselves!
(actually rubbing them with some wool gloves will make them glow a bit...so it doesn't require a lot of energy to light them up!)
But that night, there was some humidity, and apparently it's a must for the ionization to occur.
Ozone is being produced by those little arcs that are not powerful enough to make a spark
they are like those little plasma lamps that when you touch them, the arcs seems to go find your finger on the small globe
Yes it was loud that night, sounded like tons of shocks!
With the naked eye, we only see a bit of whitish light from the lines, that's why we need to do a long exposure preferably with sensitive lens and ISO settings..
For this one, I used a 28mm f1.4 lens, set the camera for 2 min. at 1000 ASA
As you can see, it was cloudy,,,it might have shown a little star trail if the sky would have been clear!
I asked Hydro Quebec for more info and they said they had seen that only once there and that I was lucky to have seen it twice in the 25 years I've been there!
Yes I was still for the exposure but we can see that the neon light moved a bit...a tad windy!
Here's something from:
http://science.howstuffworks.com/st-elmo-fire1.htm
Causes of St. Elmo's Fire: The Fire That's Not a Fire
Like lightning, St. Elmo's Fire is plasma, or ionized air that emits a glow. But while lightening is the movement of electricity from a charged cloud to the ground, St. Elmo's Fire is simply sparking, something like a shot of electrons into the air. It's a corona discharge, and it occurs when there is a significant imbalance in electrical charge, causing molecules to tear apart, sometimes resulting in a slight hissing sound.
The first step in generating St. Elmo's Fire is a thunderstorm. As you can learn in How Lightning Works, a thunderstorm creates an electrically charged atmosphere. There is a charge difference between the storm clouds and the ground, and this difference creates voltage, or electrical pressure. In between the clouds and the ground, the atoms in the air undergo changes; most important to our discussion, electrons move farther away from protons, creating an environment that allows electrons to move around freely. In other words, the air becomes a good conductor.
Once the air is conducive to the movement of electrons, those electrons continue to increase the distance between their positively charged counterpart, protons. This is ionization, and plasma is simply ionized air. The phenomenon that causes St. Elmo's Fire is a dramatic difference in charge between the air and a charged object, like the mast of a ship, the tip of an airplane wing or the 30-foot steeple of a church -- things we often think of as potential lightning rods.
When the voltage gets high enough, usually around 30,000 volts per centimeter of space, the charged object will discharge its electrical energy [source: Scientific American]. The reason why St. Elmo's Fire occurs most often on pointed objects is that a tapered surface will discharge at a lower voltage level. The tip of a steeple, mast or airplane wing presents something like a condensed surface charge.
When the air molecules tear apart, they emit light. In the case of St. Elmo's Fire, the discharge is continuous -- sometimes lasting several minutes -- and creates a constant glow. The glow is blue because different gasses glow different colors when they become plasmas. Earth's atmosphere has nitrogen and oxygen in it, and this particular combination happens to glow blue.
St. Elmo's Fire is exactly what's happening in neon tubes -- essentially a continuous spark. If Earth's atmosphere were made up of neon, St. Elmo's Fire would glow orange instead of blue. A neon tube is simply St. Elmo's Fire contained in glass. St. Elmo's Fire also behaves something like a plasma globe. One pilot described the phenomenon occurring on the windshield of her small plane while flying through a storm cloud; when she touched the inside of the windshield, blue streaks reached toward the tips of her fingers [source: USA Today].
So the next time you r hear loud sparks from a power line, get your camera gear!
I went again a week after, the air was dry as usual and no effects on the power lines, but if you move with the neon lights during the exposition, we can do some crazy pictures!
Check them out:
http://aurora-borealis.ca/en/galerie2.php?cat=25
enjoy!
Michel