Enhanced Material Assimilation in a Toroidal Plasma Using Mixed <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo>+</mml:mo><mml:mi>Ne</mml:mi></mml:mrow></mml:math> Pellet Injection and Implications to ITER
A. Matsuyama, R. Sakamoto, Ryo Yasuhara, H. Funaba, Hiroki Uehara, I. Yamada, Tomoko Kawate, M. Goto
Abstract
The ablation and assimilation of cryogenic pure ${\mathrm{H}}_{2}$ and mixed ${\mathrm{H}}_{2}+\mathrm{Ne}$ pellets, which are foreseen to be used by the ITER tokamak for mitigating thermal and electromagnetic loads of major disruptions, are observed by spatially and temporally resolved measurements. It is experimentally demonstrated that a small fraction (here $\ensuremath{\approx}5%$) of neon added to hydrogenic pellets enhances the core density assimilation with reduced outward transport for the low magnetic-field side injection. This is consistent with theoretical expectations that line radiation increased by doped neon in dense plasmoids suppresses the plasmoid pressure and reduces the $\stackrel{\ensuremath{\rightarrow}}{E}\ifmmode\times\else\texttimes\fi{}\stackrel{\ensuremath{\rightarrow}}{B}$ transport of the ablated material.