Corona discharge the electron-liberation is a high-energy photon from an atom within the plasma body relaxing after excitation from an earlier collision. The use of ionized neutral gas as a source of ionization is further diminished in a negative corona by the high-concentration of positive ions clustering around the curved electrode. Under other conditions, the collision of the positive species with the curved electrode can also cause electron liberation. The difference, then, between positive and negative coronas, in the matter of the generation of secondary electron avalanches, is that in a positive corona they are generated by the gas surrounding the plasma
Positive element Positive element In mathematics, especially functional analysis, a self-adjoint (or Hermitian) element formula_1 of a C*-algebra formula_2 is called positive if its spectrum formula_3 consists of non-negative real numbers. Moreover, an element formula_1 of a C*-algebra formula_2 is positive if and only if there is some formula_6 in formula_2 such that formula_8. A positive element is self-adjoint and thus normal. If formula_9 is a bounded linear operator on a complex Hilbert space formula_10, then this notion coincides with the condition that formula_11 is non-negative for every vector formula_12 in formula_10. Note that formula_11 is real for every formula_12 in formula_10