# What one would observe on extremely high voltages?

I am interested which physical processes generate the highest electrical voltage and what the highest measured voltage is. In everyday life, electrostatic charges e.g. while walking with socks on a carpet, can make thousands of volts and VanderGraaf generators can create a lot more voltage. Lightning strikes reach millions of volts. But can there even be much higher electric voltage in nature? What is the highest technical generated voltage?

Now I am interested what one would observe at extremely high voltages. Clearly, sparks (e.g. corona discharge) can be observed if the voltage is discharging. But assuming one has the voltage that has energies to create an electron-positron pair, i.e. $U = O(\frac{m_ec^2}{e})$ or even a voltage that has energies to create protons. What can one observe at this voltage scales?

• Ultimately, the effects of Vacuum Polarization become significant, the linearity of Maxwell's equations is believed to break down. – WetSavannaAnimal Jun 23 '16 at 14:22
• The highest voltage Van de Graaff type accelerator is the (recently defunct) 25MV vertical tandem at Oak Ridge. The very energetic beams from, say, the LHC, could in principle be used to charge up a terminal to voltages equivalent to the beam energy - the problem is insulating the terminal. In the end you would just get lightning well before getting to the GV scale here on Earth. Not sure about targeting an isolated body in space away from the solar wind. – Jon Custer Jun 23 '16 at 14:27
• Rod Vance, you didn't mean vacuum polarization which are virtual electorn-positron pairs. You meant the Schwinger limit en.wikipedia.org/wiki/Schwinger_limit with real electrons and positrons. – Luboš Motl Jun 23 '16 at 14:44
• You need to distinguish between voltage and electric field, which is measured in volts per meter. The effects you are describing are driven by electric field, not total voltage. In theory you could have enormous voltages over long distances that have small fields and no effect. – Ross Millikan Jun 23 '16 at 14:47
• @LubošMotl Thanks heaps! I was groping around for that for a while! – WetSavannaAnimal Jun 23 '16 at 22:11