Improvement of Ion Confinement in Core Electron-Root Confinement (CERC) Plasmas in Large Helical Device

Takeiri, Y.; Yokoyama, M.; Nagaoka, K.; Ida, K.; Kubo, S.; Shimozuma, Τ.; Funaba, H.; Osakabe, M.; Ikeda, K.; Tsumori, K.; Oka, Y.; Yoshinuma, M.; Morita, S.; Goto, M.; Narihara, K.; Yamada, I.; Tanaka, K.; Kaneko, O.; Komori, A.

doi:10.1585/pfr.3.s1031

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References 15 publications

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“…Transport analysis indicates that both electron and ion transport is improved in the core region with the reduction of anomalous transport. The toroidal rotation is driven in the co-direction by adding ECRH, and it is suggested that the spontaneous toroidal rotation is related to the transport improvement in the electron-root plasma [31]. Although the electron trans- port improvement is a common feature in the core electronroot confinement (CERC) plasmas [32], the ion transport improvement in CERC suggests a possible approach to achieve reactor-relevant high-temperature plasmas.…”

Section: Increase In Ion Temperature and The Related Ion Transportmentioning

confidence: 99%

Stability and Confinement Studies of High-Performance NBI Plasmas in the Large Helical Device Toward a Steady-State Helical Fusion Reactor

Takeiri

Komori

Yamada

et al. 2008

Plasma and Fusion Research

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Recent progress in plasma performance and the understanding of the related physics in the Large Helical Device is overviewed. The volume-averaged beta value is increased with an increase in the neutral beam injection (NBI) heating power, and it reached 5.0% of the reactor-relevant value. In high-β plasmas, the plasma aspect ratio should be controlled so that the Shafranov shift would be reduced, mainly to suppress transport degradation and the deterioration of the NBI heating efficiency. The operational regime of a high-density plasma with an internal diffusion barrier (IDB) has been extended, and the IDB, which was originally found using the local island divertor, has been realized in the helical divertor configuration. The central density was recorded as high as 1 × 10 21 m −3 , and the central pressure reached 130 kPa. Based on these high-density plasmas with the IDB, a new ignition scenario has been proposed. This should be a scenario specific to the helical fusion reactor, in which the helical ripple transport would be mitigated. A low-energy positive-NBI system was newly installed for an increase in the direct ion heating power. As a result, the ion temperature (T i ) exceeded 5.2 keV at a density of 1.2 × 10 19 m −3in a hydrogen plasma. Transport analysis shows improvement of ion transport, and the T i -increase tends to be accompanied by a large toroidal rotation velocity of the order of 50 km/s in the core region. The plasma properties in the extended operational regime are discussed from the perspective of a steady-state helical fusion reactor.

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Section: Increase In Ion Temperature and The Related Ion Transportmentioning

confidence: 99%

Stability and Confinement Studies of High-Performance NBI Plasmas in the Large Helical Device Toward a Steady-State Helical Fusion Reactor

Takeiri

Komori

Yamada

et al. 2008

Plasma and Fusion Research

Self Cite

View full text Add to dashboard Cite

show abstract

Improvement of Ion Confinement in Core Electron-Root Confinement (CERC) Plasmas in Large Helical Device

Cited by 1 publication

References 15 publications

Stability and Confinement Studies of High-Performance NBI Plasmas in the Large Helical Device Toward a Steady-State Helical Fusion Reactor

Stability and Confinement Studies of High-Performance NBI Plasmas in the Large Helical Device Toward a Steady-State Helical Fusion Reactor

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