View source for TJ-II:Pellet injector

[[File:TJ-II_pellet_injector.jpg|532px|thumb|right|Diagram of the TJ-II pellet injector]]
A compact multi-barrel pellet injector system is being
developed for the [[TJ-II]] stellarator (location: [[TJ-II:Sectors|sector]] B2). 
Its design is based on the
system currently installed at the MST facility (Univ. Winconsin)
and will provide maximum flexibility at minimal cost, while also
allowing for future upgrades. It is a four-barrel system destined
for use both as an active plasma diagnostic and as a plasma
fueling source. In order to achieve both objectives it will be
sufficiently flexible to allow frozen hydrogen pellets with
diameters from 0.4 to 1 mm to be formed and accelerated to
velocities between 100 and 1000 m s<sup>-1</sup>. However, floor space
restrictions and nearest-neighbor considerations limits the
overall length to <1.7 m (mechanical punch end to final guide
tube interfaces). This will be done by redesigns of the MST gun
barrel, vacuum coupling, gas dump and guide tube sectors.
Finally, the system is completed by stand-alone instrumentation
and controls, as well as LabView controlled gas manifolds.
<ref>K.J. McCarthy et al, ''A compact flexible pellet injector for the TJ-II stellarator'', [[doi:10.1109/FUSION.2005.252922|Proc. 21<sup>st</sup> IEEE/NPSS Symposium on Fusion Engineering 2005 (SOFE05)]]</ref>
<ref>K.J. McCarthy et al, ''A compact flexible pellet injector for the TJ-II stellarator'', [http://link.aip.org/link/?RSINAK/79/10F321/1 Rev. Sci. Instrum. '''79''' (2008) 10F321]</ref>
<ref>S.K. Combs, C.R. Foust, J.M. McGill, L.R. Baylor, J.B.O. Caughman, D.T. Fehling, J.H. Harris, S.J. Meitner, D.A. Rasmussen, K.J. McCarthy, M. Chamorro, R. Garcia, C. Hidalgo, M. Medrano, E. Mirones, J. Olivares, and R. Unamuno, ''A New Four-Barrel Pellet Injection System for the TJ-II Stellarator,'' [[doi:10.1109/SOFE.2011.6052244|Proceedings 2011 IEEE/NPSS 24<sup>th</sup> Symposium on Fusion Engineering, June 26–30, 2011, Chicago, Illinois]]</ref>
<ref>S. K. Combs et al., ''Results from Laboratory Testing of a New Four-Barrel Pellet Injector for the TJ-II Stellarator'', [http://epubs.ans.org/?a=19144 Fusion Science and Technology, '''64''', 3 (2013) 513]</ref>
<ref>N. Panadero, K. J. McCarthy, E. de la Cal, J. Hernández Sánchez, R. García, M. Navarro and 
TJ-II team, ''Observation of Cryogenic Hydrogen Pellet Ablation with a Fast-frame Camera System in the TJ II Stellarator'', [http://ocs.ciemat.es/EPS2016PAP/pdf/P1.008.pdf 43rd EPS Conference on Plasma Physics, Leuven, Belgium (2016) P1.008]</ref>
Recently, the system was used to inject tracer-encapsulated solid pellets.
<ref>N. Tamura, K.J. McCarthy, H. Hayashi, et al., ''Tracer-Encapsulated Solid Pellet (TESPEL) injection system for the TJ-II stellarator'', [[doi:10.1063/1.4962303|Rev. Sci. Instrum. '''87''' (2016) 11D619]]</ref>

[[File:PelletInjector15022012.jpg|500px|thumb|right|Pellet injector testing setup, February 2012]]
[[File:5456 pellet.jpg|500px|thumb|right|Image of 1 mm pellet]]
[[File:Tomo37486.gif|640px|thumb|left|[[TJ-II:Tomography|Tomographic reconstruction]] of emission from [[TJ-II:Bolometry|Bolometry]] after pellet enters [[TJ-II]] plasma]]

==References==
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