Quasi-delta negative ions density of Ar/O₂ inductively coupled plasma at very low electronegativity

One of the novel phenomena of Ar/O₂ inductively coupled plasma, the delta negative ions density profile is discovered by the fluid simulation at very low electronegativity. The anions delta is found to be formed by the collaboration of successive plasma transport phases. The plasma transport itself is affected by the delta, exhibiting many new phenomena. A new type of Helmholtz equation is devised to mathematically explain the delta forming mechanism. For revealing the physics behind, a revised spring oscillator dynamic equation has been constructed according to the Helmholtz equation, in a relevant paper Zhao S X and Li J Z (2021) Chin. Phys. B 30 055202. The investigation about the anions delta distribution is a nice prediction of new phenomenon in low temperature electronegative plasmas, waiting for the validation of related experiments.