Analysis of indefinite divertor footprint with proper orthogonal decomposition in hydrogen/deuterium plasmas in LHD. (May 2019)

• Record Type: Journal Article
• Authors: Tanaka, H.; Masuzaki, S.; Kawamura, G.; Kobayashi, M.; Suzuki, Y.; Morisaki, T.; Ohno, N.
• Is Part Of: Nuclear materials and energy. Volume 19(2019)
• Page Start: 378
• Page End: 383
• Publication Date: 2019-05
• Subjects: Divertor footprint -- Isotope effect -- Langmuir probe -- Proper orthogonal decomposition -- LHD; Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2019.03.014
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: Divertor particle fluxes on LHD were analyzed with the POD analysis method. Dominant components of divertor flux profiles in H and D plasmas were similar. Total reconstructed divertor fluxes in H plasmas were higher than D plasmas. Influences from the edge electron pressure gradient were slightly different. Abstract: Divertor particle flux signals on divertor plates were analyzed with the multivariable analysis technique, namely, proper orthogonal decomposition (POD), to characterize the indefinite divertor footprint in the Large Helical Device. To verify whether isotope effects exist in relation to the divertor plasmas, the POD outputs in hydrogen (H) and deuterium (D) plasmas were first compared by analyzing a number of discharges. It was found that the dominant components of the divertor particle flux profiles in H and D plasmas were similar, indicating no isotope effect. In addition, total reconstructed divertor particle fluxes in H plasmas were higher than those in D plasmas, suggesting an isotope effect. Furthermore, the footprint-profile modification with from the SOL-side to the private-side peak due to the edge electron pressure gradient in H and D plasmas were slightly different, relating to an isotope effect.