## 5 Conclusions and Further Remarks  
In this article, the self-coagulation theory is formally suggested for the first time and applied to explain the coagulated structures of anions that are discovered in the fluid simulations of Ar/O\({}_{2}\) and Ar/SF\({}_{6}\) ICPs. The structure is comet-shaped in Ar/O\({}_{2}\) plasma and semi-circle-shaped in Ar/SF\({}_{6}\) plasma. To keep the neutrality, the cations have to follow the anions, therefore forming the ambipolar self-coagulation process, which is similar to the ambipolar diffusion. The ambipolar self-coagulation does not create the potential gradient since the masses of attending species, anions and cations, are almost the same. This is different from the ambipolar diffusion potential of electropositive plasma that is caused by the significant mass difference of electrons and ions. Accompanied by the self-coagulation behavior of electronegative plasma, many novel phenomena occur, such as the collapse of the coagulated structure and the blue sheath. The advective self-coagulation concept is proposed to explain the origin of the blue sheath, and based on the advective type, the anion Bohm's criterion is defined. Ar/SF\({}_{6}\) discharge generates many types of anions and cations. At the ambipolar self-coagulation, each charged heavy species has its own coagulated structure, a semi-circle. Since they are coagulated, they can be treated as point-charge models. The expelling effect of Coulomb's force existing between the individual cation or anion coagulated structures leads to the collapse or at least the dispersal of relatively weak coagulated structures. The inertial effect of density quantity explains the characteristic of self-coagulation (the lighter the species, the easier it self-coagulates), and the anti-collective property of coagulated structure is observed in the collapse of coagulated structure that creates spatially radiative charge cloud. This is different from the collective interactions of electropositive or electronegative plasmas that shield the non-neutral region into the Debye's length (see Ref. [41], pp. 7-10). There is a competition between the electron-ion system and anion-cation system. At low electronegativity, such as in the Ar/O\({}_{2}\) plasma, the electron-ion system is more coupled, and hence the conventional ambipolar diffusion potential is formed (refer to Figure 1d). Nevertheless, at high electronegativity, such as in the Ar/SF\({}_{6}\) plasma, the anion-cation system is a tight couple, and the ambipolar self-coagulation of them is more predominant. Hence, the potential collapses (refer to Figure 19), and the electron dynamics are more independent. In addition, the strong physical coagulation by means of potential barrel pushing that occurs in the early discharge stage and the static gentle chemical coagulation that occurs in the late discharge stage are compared, and they give different types of density border under the coil, cliffy and smooth, in Figure 18. The coexistence of coagulated structure and dispersed discharge background waits for the validation of related experiments that utilize either the laser detachment technique of anion that is assisted by probe diagnostics [42] or spectroscopy measurement directly [43]. The monopolar self-coagulations of minor cations and electrons have significant astrophysical meaning since they can be used to simulate the formation of extraterrestrial objects. In addition, they do not create new collective interaction mechanisms of plasma, different from the ambipolar self-coagulation. Conceptualization, S.Z. ; methodology, S.Z. ; software, Y.T. ; validation, Y.T. ; formal analysis, S.Z. ; investigation, S.Z. ; resources, Y.T. ; data curation, Y.T. ; writing--original draft preparation, S.Z. ; writing--review and editing, Y.T. ; visualization, Y.T. ; supervision, Y.T. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable.