A theoretical model of H-mode transition triggered by condensed neutrals near X-point

S. Toda, S. I. Itoh, M. Yagi, Y. Miura

Research output: Contribution to journalArticle

14 Citations (Scopus)


The effects of neutrals near the X-point of tokamaks on the L/H transition are examined. Four mechanisms for bipolar losses, i.e. the loss cone loss, the bulk viscosity loss, the charge-exchange (CX) loss between ions and neutrals and the anomalous loss, occur simultaneously in high-temperature plasmas. Neutral particles near the X-point are found to trigger the H-mode transition. They cause an additional ion loss cone loss via collisions. The lower limit of the neutral density near the X-point for the onset of the H-mode transition is estimated. Neutral particles at the main plasma are shown to prevent the H-mode transition because of CX loss.

Original languageEnglish
Pages (from-to)301-312
Number of pages12
JournalPlasma Physics and Controlled Fusion
Issue number2
Publication statusPublished - Dec 1 1997


All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering
  • Condensed Matter Physics

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