ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
Four hydrogen pellets, two of 3 mm(large-closed-square)×3 mml pellets and two of 4 mmF(Slashthrough accent mark)×4 mml pellets, with the velocity of ∼2.3 km/s, were injected to OH and NB heated plasmas by a four-barrel pneumatic injector on the JT-60 tokamak. The pellet ablation profile was estimated by the measurement of the Hα emissions originating from the ablation cloud using a fiber optics array combined with the Hα -filtered multichannel photodiode. The fiber optics array consisting of ten channel bundles views the pellet pass in the vacuum vessel. The optical fiber was developed to tolerate baking up to 300 °C. The measured ablation profiles were compared with the calculated one by the neutral gas shielding model with a self-limiting effect. A good agreement was obtained between measured and calculated ablation profiles in OH plasmas; however, the fast-ion-induced ablation needed to be taken into account in the calculation for NB-heated plasmas.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1141690
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