I'm not aware of anything like "voltage density", what do you mean by that?

The potential gradient is the thing that kills you. It can either be created by a lightning strike or by voltage induced into the ground as mentioned here.

I'm talking about the potential gradient without bringing up new terminology.

> It can either be created by a lightning strike or by voltage induced into the ground as mentioned here.

If 'it' is lethal levels, then I don't think that 'or' is correct.

> You need a huge voltage density.

Does voltage density make any sense?

Probably meant gradient.

Fun fact, voltage gradient across cell membranes is typically megavolts per meter. At scale that is millivolts per nanometer, but the field strength is the same either way. Membranes are badass.

EDLC's operate at several gigavolts per meter, across a gap only atoms thick. They actually do it the same way as a cell wall -ELD stands for electrostatic double layer- by lining up two sheets of polar molecules, with charges facing each other.