Radiative and three-body recombination in the Alcator C-Mod divertor

Journal Article · Tue Jul 01 00:00:00 EDT 1997 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.872234· OSTI ID:530118

Lumma, D; Terry, J L; Lipschultz, B ^[1]

---

1. Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

Significant recombination of the majority ion species has been observed in the divertor region of Alcator C-Mod [I. H. Hutchinson {ital et al.}, Phys. Plasmas {bold 1}, 1511 (1994)] under detached conditions. This determination is made by analysis of the visible spectrum from the divertor, in particular the Balmer series line emission and the observed recombination continuum, including an apparent recombination edge at {approximately}375 nm. The analysis shows that the electron temperature in the recombining plasma is 0.8{endash}1.5 eV. The measured volume recombination rate is comparable to the rate of ion collection at the divertor plates. The dominant recombination mechanism is three-body recombination into excited states (e+e+D{sup +}{R_arrow}D{sub 0}+e), although radiative recombination (e+D{sup +}{R_arrow}D{sub 0}+h{nu}) contributes {approximately}5{percent} to the total rate. Analysis of the Balmer series line intensities (from n{sub upper}=3 through 10) shows that the upper levels of these transitions are populated primarily by recombination. Thus the brightnesses of the Balmer series (and Lyman series) are directly related to the recombination rate. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 530118
• Journal Information: Physics of Plasmas, Vol. 4, Issue 7; Other Information: PBD: Jul 1997
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION
ALCATOR DEVICE
RECOMBINATION
PLASMA DIAGNOSTICS
BALMER LINES
LYMAN LINES
DIVERTORS
ELECTRON TEMPERATURE