Direct measurement of the electron turbulence-broadening edge transport barrier to facilitate core–edge integration in tokamak fusion plasmas
| Autor: | H.Q. Wang, R. Hong, X. Jian, T.L. Rhodes, H.Y. Guo, A.W. Leonard, X. Ma, J.G. Watkins, J. Ren, B.A. Grierson, M.W Shafer, F. Scotti, T.H. Osborne, D.M. Thomas, Z. Yan |
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| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Nuclear Fusion, Vol 63, Iss 8, p 084002 (2023) |
| Druh dokumentu: | article |
| ISSN: | 1741-4326 0029-5515 |
| DOI: | 10.1088/1741-4326/acdfe2 |
| Popis: | The integration of a high-performance core and a dissipative divertor, or the so-called ‘core–edge integration,’ has been widely identified as a critical gap in the design of future fusion reactors. In this letter, we report, for the first time, direct experimental evidence of electron turbulence at the DIII-D H-mode pedestal that correlates with the broadening of the pedestal and thus facilitates core–edge integration. In agreement with gyrokinetic simulations, this electron turbulence is enhanced by high η _e ( η _e = L _n / L _T _e , where L _n is the density scale length and L _T _e is the electron temperature scale length), which is due to a strong shift between the density and temperature pedestal profiles associated with a closed divertor. The modeled turbulence drives significant heat transport with a lower pressure gradient that may broaden the pedestal to a greater degree than the empirical and theoretically predicted pedestal width scalings. Such a wide pedestal, coupled with a closed divertor, enables us to achieve a good core–edge scenario that integrates a high-temperature low-collisionality pedestal (pedestal top temperature T _e,ped > 0.8 keV and a pedestal top collisionality ν * _ped < 1) under detached divertor conditions. This paves a new path toward solving the core–edge integration issue in future fusion reactors. |
| Databáze: | Directory of Open Access Journals |
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