Isotope effects in self-organization of internal transport barrier and concomitant edge confinement degradation in steady-state LHD plasmas

T. Kobayashi, H. Takahashi, K. Nagaoka, M. Sasaki, M. Nakata, M. Yokoyama, R. Seki, M. Yoshinuma, K. Ida

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2 Citations (Scopus)

Abstract

The isotope effect, which has been a long-standing mystery in the turbulent magnetically confined plasmas, is the phenomena that the plasma generated with heavier hydrogen isotope show a mitigated transport. This is on the contrary to what is predicted with the simple scaling theory, in which the heavier ions easily diffuse because of its larger gyro-radius. Thanks to the newly developed analysis method and a comprehensive parameter scan experiment in the steady-state plasmas in the Large Helical Device (LHD), the isotope effect was clearly observed in the self-organized internal transport barrier (ITB) structure for the first time. Comparing the ITB intensity in deuterium (D) and hydrogen (H) plasmas, two distinct hydrogen isotope effects are found: stronger ITB is formed in D plasmas and a significant edge confinement degradation accompanied by the ITB formation emerges in H plasmas. This observation sheds light on a new aspect of the turbulent plasmas regarding how the basic properties of the fluid material affect the turbulent structure formation in the open-system.

Original languageEnglish
Article number15913
JournalScientific reports
Volume9
Issue number1
DOIs
Publication statusPublished - Dec 1 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General

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