A free-floating atmospheric pressure ball plasma is created when surface electricity is discharged into a solution.
In this experiment, a 4.5 kV, 0.2 millifarad capacitor was discharged into a 2-gallon bucket of water and copper sulfate. The electric discharge caused a long-lived (300 millisecond) plasma orb to rise above the water.
The surface electrode had a negative polarity, and the discharge current was in the range of 80 Amperes. The faint orange line around the plasma ball is the result of the plasma interacting with the air. The plasma in this image consists primarily of copper cations and hydroxyl anions.
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Image Credit: Caroline J. v. Wurden and Glen A. Wurden, Los Alamos