ABSTRACT
U = 1.7 (8.8)
So, using electrodes with a very low voltage across them, it is possible to accelerate an ion to a very high velocity, indeed a velocity that gives a very high equivalent temperature. This can only occur, however, if the tube is under high vacuum, where the nitrogen ion has a very low probability of colliding with another gas molecule. As soon as we introduce gas to the tube the elastic collisions between the ion and the gas quickly reduce the velocity of the ion to be in equilibrium with the background gas. We know from our experience with switching devices that they mostly operate in air at atmospheric pressure. How then does the gas between the contacts become ionized and an arc formed? The answer is to be found by considering the passage of the electrons through the gas.
