Photon Trapping Effects in DEMO Divertor Plasma

K. Hoshino, K. Sawada, R. Idei, S. Tokunaga, N. Asakura, K. Shimizu, N. Ohno

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


In the DEMO divertor, the neutral density becomes high to produce the full detachment and therefore the photon trapping can become important. In this paper, effects of the photon trapping on the DEMO divertor plasma has been studied. The pre-evaluation of the photon trapping effects on the fixed background plasma profile was carried out by using an iterative self-consistent collisional radiative model. The recombining plasma near the inner target and the private region changed to the ionizing plasma by the photon-excitation. Based on the preevaluation result, the database of the effective ionization rate coefficient including the photon transport inside a 2 mm sphere. Advantage of the 2 mm sphere approximation is that the extra calculation cost is not necessary. Iterative calculation of the SONIC including the photon trapping effects was carried out. While the electron density increased and the neutral density decreased in the wide region, the electron density decreases close to the inner strike point. This may be due to decrease in the ionization rate by decrease in the neutral density.

Original languageEnglish
Pages (from-to)657-662
Number of pages6
JournalContributions to Plasma Physics
Issue number6-8
Publication statusPublished - 2016 Aug 1
Externally publishedYes


  • DEMO divertor plasma
  • Photon trapping

ASJC Scopus subject areas

  • Condensed Matter Physics


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