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Advances in high-harmonic fast wave physics in the National Spherical Torus Experimenta)
a)Paper TI3 2, Bull. Am. Phys. Soc. 54, 255 (2009).
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Image of FIG. 1.
FIG. 1.

(a) Time averaged MPTS in the plasma scrapeoff between 0.7 and 0.75 s for two similar plasmas, one with lithium conditioning (shot 129254, thick error bars and solid thick line) and one without lithium conditioning (shot 129239, thin error bars and dashed line). Plasma separatrix is at and the HHFW antenna Faraday shield is located at . MPTS (b) and (c) immediately prior to rf heating (0.198 s, dashed line) and during 2.7 MW of heating (0.298 s, solid line) of a helium plasma (shot 135260). MPTS (d) and (e) immediately prior to rf heating (0.148 s, dashed line) and during 3.1 MW of heating (0.248 s, solid line) of a deuterium plasma (shot 129343).

Image of FIG. 2.
FIG. 2.

(a) Time evolution of the , measured by MPTS, for a sequence of deuterium plasmas with , , 1 MW of rf power starting at 0.15 s, and no Li conditioning. was adjusted from to in increments between shots. time evolution for a plasma without rf heating (black dashed line) is also plotted for comparison. Note the plasma with had an rf arc at 0.22 s. (b) and (c) measured by MPTS at 0.382 s during each discharge shown in Fig. 2(a).

Image of FIG. 3.
FIG. 3.

Time evolution of (a) measured by MPTS, (b) plasma stored energy, (c) measured by MPTS, and (d) rf power for two similar deuterium L-mode plasmas with 20 mg/min of lithium wall conditioning. Shot 129679 (solid line) had up to 1.3 MW of rf power. Shot 129677 (dashed lines) had less than 150 kW of rf power.

Image of FIG. 4.
FIG. 4.

(a) , (b) , and (c) measured by MPTS at 0.482 s for two , deuterium plasmas. One discharge had 2 MW of NBI and 1.6 MW of rf power, with , from 0.3 to 0.5 s (thick solid line, shot 129386), and the other discharge had 2 MW of NBI from 0.09 to 0.69 s (thin dashed line, shot 129381).

Image of FIG. 5.
FIG. 5.

(a) Time evolution of rf power (blue line), NBI power (dashed green line), plasma stored energy (solid black line), and lower divertor emission (red line) during an , deuterium NBI H-mode plasma with heating (shot 130608). The time evolution of the plasma stored energy for a similar plasma, but without rf heating (shot 130609), is shown by the dashed black line. rf power trips off during an antenna arc at 0.375 and 0.437 s, and is turned off at 0.5 s, in each case there is a large spike associated with a type 1 ELM. (b) Expanded time window around the time of the arc at 0.375 s and (c) around the time of the rf turn-off at 0.5 s.

Image of FIG. 6.
FIG. 6.

(a) Time evolution of the , , rf and NBI power, and the lower divertor emission during an , deuterium plasma (shot 135340) heated by 2 MW of NBI that transitions to an ELM-ing H-mode during the rf pulse at 0.29 s. This plasma had 2.7 MW of heating from 0.25 to 0.46 s. (b) and (c) measured by MPTS just before (0.282 s, blue line) and after (0.298 s, red line) the L-H transition, and at the end of the rf pulse (0.432 s, orange line). (d) rf power (black line), rf voltage reflection coefficient (blue line), and lower divertor emission (red line) during shot 135340.

Image of FIG. 7.
FIG. 7.

(a) Electron temperature, (b) electron density, and (c) electron pressure profiles measured by MPTS for two deuterium plasmas at 0.052 s, during the beginning of the current ramp-up. One discharge has 550 kW of heating coupled from 0.02 s (thick solid line) and the other discharge has no rf coupled (thin dashed line).

Image of FIG. 8.
FIG. 8.

Anisotropic C III ion heating measured near the plasma separatrix by passive ion spectroscopy. (a) Poloidal ion temperature at a major radius, during 1.2–1.3 MW of (thick solid line, shot 129679), (thin solid line, shot 129678), (dashed solid line, shot 129676) rf heating of , deuterium discharges. Also included is a shot with no rf power (shot 129677, dotted line). For the case with heating at 0.444 s, radial profiles of (b) poloidal (solid line) and toroidal ion temperature (dashed line), and (c) poloidal (solid line) and toroidal (dashed line) C III emissivity. (d) Results from a one-dimensional full wave model of the PDI-generated IBW amplitude vs pump field and rf power.

Image of FIG. 9.
FIG. 9.

(a) Toroidal velocity of C IV measured at by CHERS during a short 2 MW NBI blip at the end of a 1.1 MW rf pulse for the to scan shown in Fig. 2. (b) Toroidal velocity of C VI vs major radius for the rf heating case shown in Fig. 9(a) and Fig. 2.

Image of FIG. 10.
FIG. 10.

Visible color camera images taken during three , deuterium H-mode plasmas. (a) For plasma with only 2 MW of NBI heating (shot 130609). [(b) and (c)] For plasmas with 2 MW of NBI heating and 1.8 MW of heating (shot 130621) and 1.9 MW heating (shot 130608), respectively. (d) Radial heat flux measured by an IR camera viewing the lower divertor plate during two , deuterium H-mode plasmas, one with 2 MW of NBI (shot 135334, dashed black line) and the other with 2 MW of NBI and 2.6 MW of heating (shot 135333, red solid line).

Image of FIG. 11.
FIG. 11.

Power deposition profiles calculated by GENRAY for , deuterium H-mode plasmas with 1 MW of (a) (shot 130621) and (b) heating (shot 130608).

Image of FIG. 12.
FIG. 12.

(a) Time evolution of a series of short 65 keV NBI blips for two similar , for two similar shots 128742 and 128739. (b) rf heating pulse for shot 128739. (c) Comparison between the measured neutron rates for shot 128739 (, red line) and shot 128742 (NBI, black line). (d) FIDA signal vs major radius during the time window 0.29–0.36 s for three similar plasmas with rf heating and NBI blips (shots 128739, 128740, and 128741, red line and symbols) and a similar plasma with only NBI blips (shot 178742, blue line and symbols).

Image of FIG. 13.
FIG. 13.

Visible camera image (a) showing strap locations under uniform plasma illumination and [(b) and (c)] showing material being ejected from the antenna during plasma condition with 500 kW of rf power (enhanced online). [URL: http://dx.doi.org/10.1063/1.3371956.1]10.1063/1.3371956.1



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752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Advances in high-harmonic fast wave physics in the National Spherical Torus Experimenta)