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Title: Comparison of cryogenic (hydrogen) and TESPEL (polystyrene) pellet particle deposition in a magnetically confined plasma

Journal Article · · Europhysics Letters
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  1. Center for Energy, Environmental and Technological Research (CIEMAT), Madrid (Spain). National Fusion Lab.
  2. National Inst. for Fusion Science, Toki (Japan)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fusion and Materials for Nuclear Systems Division
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Here, a cryogenic pellet injector (PI) and tracer encapsulated solid pellet (TESPEL) injector system has been operated in combination on the stellarator TJ-II. This unique arrangement has been created by piggy-backing a TESPEL injector onto the backend of a pipe-gun–type PI. The combined injector provides a powerful new tool for comparing ablation and penetration of polystyrene TESPEL pellets and solid hydrogen pellets, as well as for contrasting subsequent pellet particle deposition and plasma perturbation under analogous plasma conditions. For instance, a significantly larger increase in plasma line-averaged electron density, and electron content, is observed after a TESPEL pellet injection compared with an equivalent cryogenic pellet injection. Moreover, for these injections from the low-magnetic-field side of the plasma cross-section, TESPEL pellets deposit electrons deeper into the plasma core than cryogenic pellets. Finally, the physics behind these observations and possible implications for pellet injection studies are discussed.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE; European Commission (EC); Ministry of Economy, Industry and Competitiveness (Spain); National Inst. for Fusion Science (NIFS); The National Inst. of Natural Sciences (NINS)
Contributing Organization:
TJ-II Team
Grant/Contract Number:
AC05-00OR22725; 633053; ENE2013-48679-R; KEIN1102; KEIN1104; UFEX106
OSTI ID:
1427621
Journal Information:
Europhysics Letters, Vol. 120, Issue 2; ISSN 0295-5075
Publisher:
IOP PublishingCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 10 works
Citation information provided by
Web of Science

Cited By (6)

Tracer-Encapsulated Solid Pellet (TESPEL) injection system for Wendelstein 7-X journal October 2018
The impact of fast electrons on pellet injection in the stellarator TJ-II journal November 2018
Plasma termination by excess pellet fueling and impurity injection in TJ-II, the Large Helical Device and Wendelstein 7-X journal May 2019
Hollow pellet injection for magnetic fusion journal June 2019
Overview of recent TJ-II stellarator results journal July 2019
Overview of recent TJ-II stellarator results text January 2019

Figures / Tables (6)

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Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY