VSE knjižnice (vzajemna bibliografsko-kataložna baza podatkov COBIB.SI)
  • Towards a theory of collisionless-discharges with imbalanced global charge-outfluxes
    Jelić, Nikola ; Kos, Leon, 1966-
    Conventional Tonks & Langmuir collission-free plasma-sheath theory, which for decades serves as an archetype in formulating and solving a coupled set of Newton and Poison equations in a bounded ... laboratory, technology-oriented and fusion-related plasmas, is intrinsically limited to relatively simple physical scenarios in which internal electric curent are carried out exclusively by charged particles, which is clearly inaplicable for modelling the transient phenomena during a discharge development and decay. This seems to be quite a satisfactory approach when such a system is supposed to be a good prototype for e.g., resolving theoretically or in kinetic simulations the plasma-sheath boundary under various assumptions of volume plasma production and electron density distributions as functions of local plasma potential, of course, providing that such a problem is under given particular assumptions solvable at all, by either of above methods. Namelly the plasma-sheath problem is still not only a strongly non-linear one, but depends on a considerable numbers of parameters of which just a single one, such as ion-source velocity distribution function, i.e., its particular shape and width (temperature) prevents generalizing kinetic results into a user-friendly terminology of statistically averaged, i.e., fluid quantities, exept under e.g., approximation of pure Maxellian or simpler ionsources [L. Kos et al., Phys. Plasmas 16, 093503 (2009); N. Jelić et al., Phys. Plasmas 16, 123503 (2009)]. However, these difficulties could not be an excuse for a prior disregarding all possible solutions in which the rates of positive and negative charges leaving the discharge-domain is not ballanced, for e.g., a simple reason that one of charged population could be better/worse confined than the oposite one. In fact, this physical scenario should be regarded as a rule while a strict steady discharge is, actually a true exception which we are able to realize just on expense of a prior relaxed boundary conditions, which, in fact resut in a low plasma density. Within present investigation we perform a series of CPU-expensive numerical simulations towards obtaining periodically-relaxing time-dependent solutions that a dense plasma still can persist as a steady (properly averaged in time) discharge. A theoretical approach with first results regarding relevant plasma parameters (such as time-averaged plasma-profile density and critical ion-velocity at the plasma edge) is presented.
    Vir: Book of abstracts (Str. 77-78)
    Vrsta gradiva - prispevek na konferenci
    Leto - 2014
    Jezik - angleški
    COBISS.SI-ID - 13957915

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