Flash close-up

I wanted to see what the flash produces before and during the flash.
While waiting for the trigger the cathode and anode produce a lot of corona and corresponding ultraviolet light.
During the flash a spectrum of oxygen and nitrogen is produced and it seems some copper (green) as well.
The spark also contains a lot of infrared radiation, which causes the red tail in the highlights of some fast moving objects. To my surprise the trace of the spark was very different each flash. It seems Edgerton cut a groove in the inner glass tube to guide the spark.

The gap has 20.000 Volts and a capacitor of 0.05 micro Farads. That equals an energy of 0.5*C*V^2=10 Joules. Since all of that energy is released in about 0.5 microseconds, this means a the flash has a peak power of 20 MegaWatts. Imagine twenty thousand floodlights of 1000 Watts, all illuminating a gap of 20 mm…. That also gives an impression how incredibly short half a microsecond is.

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