Plasma radiometry with 30 chord resolution for fast transients in the DIII-D tokamak

Gray, D.S.; Hollmann, E. M.; Luckhardt, S.; Chalfant, J.; Chousal, L.; Hernández, R.; Jones, E. P.; Kellman, A.G.

doi:10.1063/1.1787149

Cited by 15 publications

(13 citation statements)

References 9 publications

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“…The density was increased in a sequence of discharges, from hn e i/ n G = 0.40-0.8. (n G is the Greenwald limit) The principal measurements were made by the fast radiometer array [7] (DISRAD2), a fast scanning probe, [8] Beam emission spectroscopy [9] (BES), reflectometry [10] and charge exchange recombination spectroscopy, CER [11]. The fast scanning probe array features five tips that sense current, I, saturation current, I sat , and floating potential, U f .…”

Section: Methodsmentioning

confidence: 99%

ELM-induced plasma transport in the DIII-D SOL

Boedo

Rudakov

Hollmann

et al. 2005

Journal of Nuclear Materials

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High temporal and spatial resolution measurements in the boundary of the DIII-D tokamak show that edge localized modes (ELMs) are composed of fast bursts of hot, dense plasma lasting $25 ls each that travel radially starting at the separatrix at $450 m/s and rotate in the scrape off layer (SOL), convecting particles and energy to the SOL and walls. The temperature and density in the ELM plasma initially correspond to those at the top of the density pedestal but decay with radius in the SOL. The temperature decay length ($1.2-1.5 cm) is much shorter than the density decay length ($3-8 cm), which in turn decreases with increasing pedestal density. The local particle and energy flux at the wall during the bursts are 10-50% ($1-2 · 10 21 m À2 s À1 ) and 1-2% ($20-30 kW/m 2 ) respectively of the LCFS average fluxes, thus particles are transported radially much more efficiently that heat.

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Section: Methodsmentioning

confidence: 99%

ELM-induced plasma transport in the DIII-D SOL

Boedo

Rudakov

Hollmann

et al. 2005

Journal of Nuclear Materials

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“…Figure 1(a) shows the location of the MGI port used in these experiments, along with the lower single-null discharge shape. The resulting radiated power during the fast shutdown is measured at two toroidal locations, by poloidal fan array radiometers [18] whose locations relative to the MGI port are shown in figure 1. Magnetic measurements of the MHD activity are provided by in-vessel probes distributed across the DIII-D vessel, as described in [19,20].…”

Section: Phenomenology Of Mhd Activity During Mgimentioning

confidence: 99%

Characterization of MHD activity and its influence on radiation asymmetries during massive gas injection in DIII-D

Shiraki¹,

Commaux²,

Baylor³

et al. 2015

Nucl. Fusion

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Measurements from the DIII-D tokamak show that toroidal radiation asymmetries during fast shutdown by massive gas injection (MGI) are largely driven by n = 1 magnetohydrodynamic modes during the thermal quench. The phenomenology of these modes, which are driven unstable by profile changes as the thermal energy is quenched, is described based on detailed magnetic measurements. The toroidal evolution of the dominantly n = 1 perturbation is understood to be a function of three parameters: the location of the MGI port, pre-MGI plasma rotation, and n = 1 error fields. The resulting level of radiation asymmetry in these DIII-D plasmas is modest, with a toroidal peaking factor (TPF) of 1.2 ± 0.1 for the total thermal quench energy and 1.4 ± 0.3 for the peak radiated power, both of which are below the estimated limit for ITER (TPF ≈ 2) [M. Sugihara et al., Nucl. Fusion 47, 337 (2007)].

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“…The directed geometry has a longer gas pressure rise time (~2-4 ms) but has the advantage of being aimed more toward the center of the plasma. Electron temperature is measured using Thomson scattering and electron cyclotron emission (ECE), while total radiated power is measured using an XUV photodiode array [14]. The jet UV emission spectrum is measured using a core tangential UV survey spectrometer.…”

Section: Experimental Layoutmentioning

confidence: 99%

Measurements of impurity and heat dynamics during noble gas jet-initiated fast plasma shutdown for disruption mitigation in DIII-D

et al. 2005

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IAEA-CN-116/EX/10-6Ra This is a preprint of a paper intended for presentation at a scientific meeting. Because of the provisional nature of its content and since changes of substance or detail may have to be made before publication, the preprint is made available on the understanding that it will not be cited in the literature or in any way be reproduced in its present form. The views expressed and the statements made remain the responsibility of the named author(s); the views do not necessarily reflect those of the government of the designating Member State(s) or of the designating organization(s). In particular, neither the IAEA nor any other organization or body sponsoring this meeting can be held responsible for any material reproduced in this preprint.

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Plasma radiometry with 30 chord resolution for fast transients in the DIII-D tokamak

Cited by 15 publications

References 9 publications

ELM-induced plasma transport in the DIII-D SOL

ELM-induced plasma transport in the DIII-D SOL

Characterization of MHD activity and its influence on radiation asymmetries during massive gas injection in DIII-D

Measurements of impurity and heat dynamics during noble gas jet-initiated fast plasma shutdown for disruption mitigation in DIII-D

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