TJ-II:Plasma Wall Interaction: Difference between revisions

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In the course of time, TJ-II has been operated with the following types of wall:
In the course of time, TJ-II has been operated with the following types of wall:


* Metal wall <ref>[http://dx.doi.org/10.1088/0741-3335/43/8/302 F.L. Tabarés et al, ''Edge characteristics and global confinement of electron cyclotron resonance heated plasmas in the TJ-II Stellarator'', Plasma Phys. Control. Fusion '''43''' (2001) 1023-1037  ]</ref>
* Metal wall <ref>[http://dx.doi.org/10.1016/S0022-3115(98)00861-7 F.L. Tabarés et al, ''Plasma–wall interaction in the Spanish stellarator TJ-II Diagnostics and first results'', Journal of Nuclear Materials '''266-269''' (1999) 1273-1278]</ref> <ref>[http://dx.doi.org/10.1088/0741-3335/43/8/302 F.L. Tabarés et al, ''Edge characteristics and global confinement of electron cyclotron resonance heated plasmas in the TJ-II Stellarator'', Plasma Phys. Control. Fusion '''43''' (2001) 1023-1037  ]</ref>
* Boron-coated wall <ref>[http://dx.doi.org/10.1016/S0042-207X(02)00211-7 D. Tafalla and F.L. Tabarés, ''First boronization of the TJ-II stellarator'', Vacuum '''67''', Issues 3-4 (2002) 393-397]</ref> (starting 2002)
* Boron-coated wall <ref>[http://dx.doi.org/10.1016/S0042-207X(02)00211-7 D. Tafalla and F.L. Tabarés, ''First boronization of the TJ-II stellarator'', Vacuum '''67''', Issues 3-4 (2002) 393-397]</ref> (starting 2002)
* Lithium-coated wall <ref>[http://dx.doi.org/10.1088/0741-3335/50/12/124051 F.L. Tabarés at al, ''Plasma performance and confinement in the TJ-II stellarator with lithium-coated walls'', Plasma Phys. Control. Fusion '''50''' (2008) 124051]</ref> <ref>[http://dx.doi.org/10.1016/j.jnucmat.2009.01.224 J. Sánchez et al, ''Impact of lithium-coated walls on plasma performance in the TJ-II stellarator'', Journal of Nuclear Materials '''390-391''' (2009) 852-857]</ref> <ref>[http://dx.doi.org/10.1088/0029-5515/49/10/104018 J. Sánchez et al, ''Confinement transitions in TJ-II under Li-coated wall conditions'', Nucl. Fusion '''49''' (2009) 104018]</ref>(starting 2007)
* Lithium-coated wall <ref>[http://dx.doi.org/10.1088/0741-3335/50/12/124051 F.L. Tabarés at al, ''Plasma performance and confinement in the TJ-II stellarator with lithium-coated walls'', Plasma Phys. Control. Fusion '''50''' (2008) 124051]</ref> <ref>[http://dx.doi.org/10.1016/j.jnucmat.2009.01.224 J. Sánchez et al, ''Impact of lithium-coated walls on plasma performance in the TJ-II stellarator'', Journal of Nuclear Materials '''390-391''' (2009) 852-857]</ref> <ref>[http://dx.doi.org/10.1088/0029-5515/49/10/104018 J. Sánchez et al, ''Confinement transitions in TJ-II under Li-coated wall conditions'', Nucl. Fusion '''49''' (2009) 104018]</ref>(starting 2007)

Revision as of 07:46, 24 September 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] [7]
  • Boron-coated wall [8] (starting 2002)
  • Lithium-coated wall [9] [10] [11](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

  1. ↑ R. Carrasco, Hybrid baking system for the vacuum vessel of the Spanish stellarator TJ-II, Proc. 18th Symposium on Fusion Engineering (1999) 231-234
  2. ↑ D. Tafalla and F.L. Tabarés, Wall conditioning and density control in the TJ-II stellarator, Journal of Nuclear Materials 290-293 (2001) 1195-1198
  3. ↑ D. Tafalla and F.L. Tabarés, Wall conditioning of TJ-II stellarator by glow discharge, Vacuum 64, Issues 3-4 (2002) 411-415
  4. ↑ J. Botija et al, Vacuum vessel, wall protection, pumping system and poloidallimiters of the Spanish stellarator TJ-II, 15th IEEE/NPSS Symposium on Fusion Engineering, Vol. 1 (1993) 529-532
  5. ↑ F.L. Tabarés et al, Density control and plasma edge characterisation of ECRH heated plasmas in the TJ-II stellarator, Journal of Nuclear Materials 290-293 (2001) 748-752
  6. ↑ F.L. Tabarés et al, Plasma–wall interaction in the Spanish stellarator TJ-II Diagnostics and first results, Journal of Nuclear Materials 266-269 (1999) 1273-1278
  7. ↑ F.L. Tabarés et al, Edge characteristics and global confinement of electron cyclotron resonance heated plasmas in the TJ-II Stellarator, Plasma Phys. Control. Fusion 43 (2001) 1023-1037
  8. ↑ D. Tafalla and F.L. Tabarés, First boronization of the TJ-II stellarator, Vacuum 67, Issues 3-4 (2002) 393-397
  9. ↑ F.L. Tabarés at al, Plasma performance and confinement in the TJ-II stellarator with lithium-coated walls, Plasma Phys. Control. Fusion 50 (2008) 124051
  10. ↑ J. Sánchez et al, Impact of lithium-coated walls on plasma performance in the TJ-II stellarator, Journal of Nuclear Materials 390-391 (2009) 852-857
  11. ↑ J. Sánchez et al, Confinement transitions in TJ-II under Li-coated wall conditions, Nucl. Fusion 49 (2009) 104018
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