Impurity Confinement and Transport in High Confinement Regimes without ELMs on DIII-D
Authors: B.A. Grierson, K.H. Burrell, R.M. Nazikian, W.M. Solomon, et al.
Abstract: Impurity transport in the DIII-D tokamak [J.L. Luxon, Nucl. Fusion 42, 614 (2002)] is investigated in stationary high confinement (H-mode) regimes without ELMs. In plasmas maintained by RMP ELM-suppression and QH-mode the confinement time of fluorine (Z=9) is equivalent to that in ELMing discharges with 40 Hz ELMs. Particle confinement time compared to the energy con nement time is in the range of τp/τe ≈ 2–3. In QH operation, the impurity con nement time is shown to be inversely proportional to the magnitude of the EHO fluctuation intensity. Transport coefficients are derived from the time evolution of the impurity density profile and compared to neoclassical and turbulent transport models, displaying reasonable agreement in regions of the plasma unaffected by core MHD instabilities.
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Submitted to: Physics of Plasmas
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