Collisional-radiative model

The population of these vibrational states can be described by a collisional-radiative model [66,67], where the population density is mainly a function of Te. It can explain why at low Te (high-density case) the energies of the dissociated atoms can be higher than at higher Te at low Te more molecules are dissociating from the ground state delivering atoms with 2.2 eV, whereas... 

From inspecting the atomic database of the EIRENE code [31], which is used in many applications to a large number of different tokamaks, including for the ITER design, in particular its collisional-radiative models for molecules, it was clear that matters can be more complicated. The relaxation time for establishing a vibrational distribution of the ground state molecule is comparable to the transport time of the molecule, hence the applicability of local collisional-radiative approximations is questionable. Furthermore, one of the two atoms created in dissociative recombination is electronically excited, and, hence, can be ionized very effectively even at low divertor plasma temperatures (instead of radiative decay). In this case, the whole chain of reactions would be just an enhanced ( molecular activated ) dissociation (MAD, i.e., dissociative excitation of those H]]", which have been produced... 

The author would like to mention the contributions of D. Wunderlich for the calculations with the collisional-radiative model, D. Reiter and D. Coster for running the B2-EIRENE code and the ASDEX Upgrade Team as well as the plasma spectroscopic team at Augsburg University for their assistance. 

Thus, with knowledge of the factor S/XB, which S = a ve), X = cr xgve), and B = T, the photon fluxes can be converted into particle fluxes. In general terms the excitation rate X can be replaced by a population rate provided by a collisional-radiative model, which treats the excitation and de-excitation from all possible levels into the emitting one. The same holds for all possible ionization processes. In the case of molecules not only ionization but also dissociation will play a significant role, and, therefore, the ionization rate S... 

In order to convert the photons into molecular fluxes the D/XB-value for the Fulcher-a band is needed. For this purpose a collisional-radiative model (CRM) has been set up which includes all levels that could contribute to the population of the 3p 3f7u state. Figure 6.12 shows that under the conditions of the TEXTOR scrape-off layer the levels 2p 3flu and 2s 3X+ also contribute to... 

Fig. 6.13. Calculations of D/XB for the Fulcher-band from the collisional-radiative model CRMOL. The solid dot is an experimentally obtained value via a calibrated...

State selective dielectronic recombination rate coefficients from Li-like ions to Be-like ions (C, O, Ne, Fe ions) and for carbon L-shell ions have been calculated [10-13]. These data are used to develop collisional-radiative models including dielectronic recombination to excited states [14-17]. The population kinetics of L-shell ions and atoms have been developed and their results have been applied to plasma diagnostics. 

Mizuochi, J. Sakamoto, T. Matsuura, H. Akatsuka, H. (2010). Evaluation of Electron Energy Distribution Function in Microwave Discharge Plasmas by Sp>ectroscopic Diagnostics with Collisional Radiative Model. Jpn. J. Appl Phys., Vol. 49, No. 3, (March 2010), pp. 036001-1-036001-14, ISSN 1347-4065... 

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