Density fluctuation statistics and turbulence spreading at the edge of L-mode plasmas

被引:1
|
作者
Khabanov, F. O. [1 ]
Hong, R. [2 ]
Diamond, P. H. [3 ]
Tynan, G. R. [3 ]
Yan, Z. [1 ]
McKee, G. R. [1 ]
Chrystal, C. [4 ]
Scotti, F. [5 ]
Yu, G. [6 ]
Zamperini, S. A. [4 ]
Zhu, Y. [6 ]
机构
[1] Univ Wisconsin, Madison, WI 53705 USA
[2] Univ Calif Los Angeles, Los Angeles, CA USA
[3] Univ Calif San Diego, San Diego, CA USA
[4] Gen Atom, San Diego, CA USA
[5] Lawrence Livermore Natl Lab, Livermore, CA USA
[6] Univ Calif Davis, Davis, CA USA
关键词
tokamak; edge density fluctuations; turbulence spreading; TRANSPORT; VELOCIMETRY; BOUNDARY;
D O I
10.1088/1741-4326/ad820d
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
Long-wavelength density fluctuations (k rho(i) <1) are studied using beam emission spectroscopy (BES) at the edge of DIII-D L-mode plasmas (rho = 0.88-1.1) in scenarios with electron cyclotron heating (ECH) power ramp (P-ECH up to 1.5 MW), neutral beam injection (NBI) power ramp (P-NBI up to 2.5 MW), and injected torque scan (-1 <T-inj <0.6 Nm). We find that broadband turbulent density fluctuations (f similar to 20-120 kHz) have a non-Gaussian distribution. The skewness of delta n/n changes sign from negative at rho <0.95-0.97 to positive at rho > 0.97, indicating the prevalence of density 'voids' at inner radii and density 'blobs' at outer radii and outside of the separatrix. The turbulence intensity flux <(v(r)) over tilde(n2) over tilde > is calculated to characterize turbulence spreading at the plasma edge. During ECH/NBI power ramps and at counter-Ip injected torque, <(v(r)) over tilde(n2) over tilde > is directed inward inside the separatrix, which is evidence of inward spreading of turbulence intensity from the edge gradient region caused by the inner propagation of density 'voids'. Significantly weaker <(v(r)) over tilde(n2) over tilde > is observed with co-I-p torque. A correlation between co-Ip torque, turbulence intensity delta n/n at rho = 0.97, and increased srape-off layer (SOL) heat flux decay length lambda(q) is found in the torque scan scenario, showing that edge turbulence plays a material role in determining the SOL conditions and heat flux width.
引用
收藏
页数:16
相关论文
共 50 条
  • [31] THE ROLE OF CURRENT PROFILE BROADENING IN L-MODE AND H-MODE PLASMAS
    CHRISTIANSEN, JP
    CORDEY, JG
    NUCLEAR FUSION, 1990, 30 (04) : 599 - 610
  • [32] Electron heat transport in shaped TCV L-mode plasmas
    Camenen, Y
    Pochelon, A
    Bottino, A
    Coda, S
    Ryter, F
    Sauter, O
    Behn, R
    Goodman, TP
    Henderson, MA
    Karpushov, A
    Porte, L
    Zhuang, G
    PLASMA PHYSICS AND CONTROLLED FUSION, 2005, 47 (11) : 1971 - 1987
  • [33] Turbulence during H- and L-mode plasmas in the scrape-off layer of the ASDEX Upgrade tokamak
    Antar, G. Y.
    Tsalas, M.
    Wolfrum, E.
    Rohde, V.
    PLASMA PHYSICS AND CONTROLLED FUSION, 2008, 50 (09)
  • [34] Light impurity transport in JET ILW L-mode plasmas
    Bonanomi, N.
    Mantica, P.
    Giroud, C.
    Angioni, C.
    Manas, P.
    Menmuir, S.
    Abduallev, S.
    Abhangi, M.
    Abreu, P.
    Afzal, M.
    Aggarwal, K. M.
    Ahlgren, T.
    Ahn, J. H.
    Aho-Mantila, L.
    Aiba, N.
    Airila, M.
    Albanese, R.
    Aldred, V.
    Alegre, D.
    Alessi, E.
    Aleynikov, P.
    Alfier, A.
    Alkseev, A.
    Allinson, M.
    Alper, B.
    Alves, E.
    Ambrosino, G.
    Ambrosino, R.
    Amicucci, L.
    Amosov, V.
    Sunden, E. Andersson
    Angelone, M.
    Anghel, M.
    Angioni, C.
    Appel, L.
    Appelbee, C.
    Arena, P.
    Ariola, M.
    Arnichand, H.
    Arshad, S.
    Ash, A.
    Ashikawa, N.
    Aslanyan, V.
    Asunta, O.
    Auriemma, F.
    Austin, Y.
    Avotina, L.
    Axton, M. D.
    Ayres, C.
    Bacharis, M.
    NUCLEAR FUSION, 2018, 58 (03)
  • [35] Simulations of drift resistive ballooning L-mode turbulence in the edge plasma of the DIII-D tokamak
    Cohen, B. I.
    Umansky, M. V.
    Nevins, W. M.
    Makowski, M. A.
    Boedo, J. A.
    Rudakov, D. L.
    McKee, G. R.
    Yan, Z.
    Groebner, R. J.
    PHYSICS OF PLASMAS, 2013, 20 (05)
  • [36] Heat loads in inboard limited L-mode plasmas in TCV
    Nespoli, F.
    Labit, B.
    Furno, I.
    Canal, G. P.
    Fasoli, A.
    JOURNAL OF NUCLEAR MATERIALS, 2015, 463 : 393 - 396
  • [37] Characterizing the flow and turbulence structure near the last closed flux surface in L-mode plasmas of ASDEX Upgrade
    Nishizawa, T.
    Manz, P.
    Grenfell, G.
    Griener, M.
    Wendler, D.
    Brida, D.
    Kriete, D. M.
    Dux, R.
    Kobayashi, T.
    Sasaki, M.
    PHYSICS OF PLASMAS, 2022, 29 (07)
  • [39] Designing a VH-mode core/L-mode edge discharge
    General Atomics, San Diego, United States
    Plasma Phys Controlled Fusion, 8 (1461-1464):
  • [40] Interpretation of the hydrogen isotope effect on the density limit in JET-ILW L-mode plasmas using EDGE2D-EIRENE
    Solokha, V
    Groth, M.
    Corrigan, G.
    Wiesen, S.
    PHYSICA SCRIPTA, 2021, 96 (12)