TJ-II:Plasma Wall Interaction: Difference between revisions

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== Limiters ==
== Limiters ==


TJ-II is fitted with two mobile [[TJ-II:Limiter|limiters]]. Nevertheless, the main interaction between the plasma and the wall occurs at the central "groove".  
TJ-II is fitted with two mobile [[TJ-II:Limiter|limiters]]. Nevertheless, the main interaction between the plasma and the wall occurs at the central "groove".
<ref>[http://dx.doi.org/10.1109/FUSION.1993.518387 J. Botija et al, ''Vacuum vessel, wall protection, pumping system and poloidallimiters of the Spanish stellarator TJ-II'', 15<sup>th</sup> IEEE/NPSS Symposium on Fusion Engineering, Vol. 1 (1993) 529-532]</ref>


== Wall conditioning ==
== Wall conditioning ==

Revision as of 22:57, 20 August 2009

To condition the wall of the TJ-II vacuum vessel, a number of techniques is used, such as a baking system. [1]

Glow Discharge Cleaning

Glow discharge cleaning is routinely used at TJ-II. [2] [3]

Limiters

TJ-II is fitted with two mobile limiters. Nevertheless, the main interaction between the plasma and the wall occurs at the central "groove". [4]

Wall conditioning

TJ-II retractable Lithium evaporation oven in action

Careful control of wall conditions is essential for successful operation. [5]

The walls can be coated by various materials, using a set of 4 evaporation ovens: two fixed and two mounted on retractable manipulators. In the course of time, TJ-II has been operated with the following types of wall:

  • Metal wall [6]
  • Boron-coated wall [7] (starting 2002)
  • Lithium-coated wall [8] [9] (starting 2007)

TJ-II was the first stellarator to be operated with Lithium-coated walls. The lithium coating has led to much improved density control.

References