Close coupling approach for heavy particle collisions with an excited atom: transitions betweenn=3 states in He

Abstract

The close coupling (CC) equations in the impact parameter (IP) representation are considered. Calculations for transitions in the 3s–3p–3d He atom system induced by collisions with single charged ions were carried out. Results are compared with those obtained in the frame of the Born approach. The effects of stepped transitions, normalization, channel coupling and their dependence on interaction strength are discussed.

Status of electron temperature and density measurement with beam emission spectroscopy on thermal helium at TEXTOR

“…Collisions with heavy particles at thermal velocities may contribute only for transitions with n = 0 and for the charge transfer with a small resonance defect. The rate coefficients for excitation by deuterons were calculated using the CC method (code ATCC [13]) for the most important transitions 3l-3l and in the normalized Born approximation [31] for other transitions.…”

“…In order to investigate the impact of the processes neglected so far and the role of a renewed set of atomic data on the measurement results we developed a new CRM. This model uses a renewed set of atomic data as a compilation of rate coefficients calculated with the ATOM code [13] and a collection from different atomic databases. To solve the kinetic equations of the penetrating He atoms, the GKU code [14] is used.…”

Determination of rate coefficients for fusion-relevant atoms and molecules by modelling and measurement in the boundary layer of TEXTOR

“…An alternative in this case is to produce spectra in the same wavelength range either in a simulator with a boundary-like plasma of 10 12 cm −3 < n e < 2 × 10 13 cm −3 and 5 eV < T e < 50 eV [8,9] or directly in a tokamak where the respective elements are introduced either by gas blow or laser blow-off. The principle of these experiments is to reverse equation (2),…”

“…The tokamak TEXTOR with its spatially resolving and absolutely calibrated spectroscopy on limiter locks and other PFCs, which are equipped with gas injection systems, is especially suited for such kind of measurements. Several codes (ATOM [1], ATCC [2], GKU for atoms and ions [3]; CRMOL for hydrogen molecules [4]; ERO for erosion and deposition [5]) allow the calculation of level populations for boundary plasma parameter conditions. The particles investigated were Li, He, B, C, O, Si, Mo and W as atoms and/or ions as well as hydrogen (with its isotopomeres) and hydrocarbon molecules (with their radical dissociation products).…”