Plasma (physics) potential in the space between charged particles, independent of how it can be measured, is called the "plasma potential", or the "space potential". If an electrode is inserted into a plasma, its potential will generally lie considerably below the plasma potential due to what is termed a Debye sheath. The good electrical conductivity of plasmas makes their electric fields very small. This results in the important concept of "quasineutrality", which says the density of negative charges is approximately equal to the density of positive charges over large volumes of the plasma (formula_6), but on the scale of the Debye length
Lucky numbers of Euler Lucky numbers of Euler Euler's “lucky” numbers are positive integers "n" such that for all integers "k" with , the polynomial produces a prime number. When "k" is equal to "n", the value cannot be prime anymore since is divisible by "n". Since the polynomial can be rewritten as , using the integers "k" with produces the same set of numbers as . Leonhard Euler published the polynomial which produces prime numbers for all integer values of "k" from 1 to 40. Only 7 lucky numbers of Euler exist, namely 1, 2, 3, 5, 11, 17 and 41 . The