TJ-II:Plasma Wall Interaction: Difference between revisions
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To condition the wall of the [[TJ-II]] vacuum vessel, a number of techniques is used, | To condition the wall of the [[TJ-II]] [[TJ-II:Vacuum system|vacuum vessel]], a number of techniques is used, | ||
such as a baking system. | such as a baking system. | ||
<ref> | <ref>R. Carrasco, '' Hybrid baking system for the vacuum vessel of the Spanish stellarator TJ-II'', [[doi:10.1109/FUSION.1999.849826|Proc. 18<sup>th</sup> Symposium on Fusion Engineering (1999) 231-234]]</ref> | ||
Currently, this system is no longer in use. | |||
== Glow Discharge Cleaning == | |||
Glow discharge cleaning is routinely used at TJ-II. | |||
<ref>D. Tafalla and F.L. Tabarés, ''Wall conditioning and density control in the TJ-II stellarator'', [[doi:10.1016/S0022-3115(00)00672-3|Journal of Nuclear Materials '''290-293''' (2001) 1195-1198]]</ref> | |||
<ref>D. Tafalla and F.L. Tabarés, ''Wall conditioning of TJ-II stellarator by glow discharge'', [[doi:10.1016/S0042-207X(01)00301-3|Vacuum '''64''', Issues 3-4 (2002) 411-415]]</ref> | |||
== 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". | |||
<ref>J. Botija et al, ''Vacuum vessel, wall protection, pumping system and poloidal limiters of the Spanish stellarator TJ-II'', [[doi:10.1109/FUSION.1993.518387|15<sup>th</sup> IEEE/NPSS Symposium on Fusion Engineering, Vol. 1 (1993) 529-532]]</ref> | |||
== Wall conditioning == | |||
[[File:TJ-II_Lithium_oven.jpg|300px|thumb|right|TJ-II retractable Lithium evaporation oven in action]] | |||
Careful control of wall conditions is essential for successful operation. | |||
<ref>F.L. Tabarés et al, ''Density control and plasma edge characterisation of ECRH heated plasmas in the TJ-II stellarator'', [[doi:10.1016/S0022-3115(00)00490-6|Journal of Nuclear Materials '''290-293''' (2001) 748-752]]</ref> | |||
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 <ref>F.L. Tabarés et al, ''Plasma–wall interaction in the Spanish stellarator TJ-II Diagnostics and first results'', [[doi:10.1016/S0022-3115(98)00861-7|Journal of Nuclear Materials '''266-269''' (1999) 1273-1278]]</ref> <ref>F.L. Tabarés et al, ''Edge characteristics and global confinement of electron cyclotron resonance heated plasmas in the TJ-II Stellarator'', [[doi:10.1088/0741-3335/43/8/302|Plasma Phys. Control. Fusion '''43''' (2001) 1023-1037 ]]</ref> | |||
* Boron-coated wall <ref>D. Tafalla and F.L. Tabarés, ''First boronization of the TJ-II stellarator'', [[doi:10.1016/S0042-207X(02)00211-7|Vacuum '''67''', Issues 3-4 (2002) 393-397]]</ref> (starting 2002) | |||
* Lithium-coated wall <ref>F.L. Tabarés at al, ''Plasma performance and confinement in the TJ-II stellarator with lithium-coated walls'', [[doi:10.1088/0741-3335/50/12/124051|Plasma Phys. Control. Fusion '''50''' (2008) 124051]]</ref> <ref>J. Sánchez et al, ''Impact of lithium-coated walls on plasma performance in the TJ-II stellarator'', [[doi:10.1016/j.jnucmat.2009.01.224|Journal of Nuclear Materials '''390-391''' (2009) 852-857]]</ref> <ref>J. Sánchez et al, ''Confinement transitions in TJ-II under Li-coated wall conditions'', [[doi:10.1088/0029-5515/49/10/104018|Nucl. Fusion '''49''' (2009) 104018]]</ref><ref>F.L. Tabarés, M. Ochando, D. Tafalla, F. Medina, K. McCarthy, J.M. Fontdecaba, M. Liniers, J. Guasp, E. Ascasíbar, T. Estrada, I. Pastor, TJ-II Team, ''Energy and Particle Balance Studies Under Full Boron and Lithium-Coated Walls in TJ-II'', [[doi:10.1002/ctpp.200900046|Contrib. Plasma Phys. '''50''', 6-7 (2010) 610–615]]</ref>(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 == | == References == | ||
<references /> | <references /> |
Latest revision as of 19:05, 16 April 2018
To condition the wall of the TJ-II vacuum vessel, a number of techniques is used, such as a baking system. [1] Currently, this system is no longer in use.
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
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][12](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
- ↑ R. Carrasco, Hybrid baking system for the vacuum vessel of the Spanish stellarator TJ-II, Proc. 18th Symposium on Fusion Engineering (1999) 231-234
- ↑ 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
- ↑ D. Tafalla and F.L. Tabarés, Wall conditioning of TJ-II stellarator by glow discharge, Vacuum 64, Issues 3-4 (2002) 411-415
- ↑ J. Botija et al, Vacuum vessel, wall protection, pumping system and poloidal limiters of the Spanish stellarator TJ-II, 15th IEEE/NPSS Symposium on Fusion Engineering, Vol. 1 (1993) 529-532
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ D. Tafalla and F.L. Tabarés, First boronization of the TJ-II stellarator, Vacuum 67, Issues 3-4 (2002) 393-397
- ↑ 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
- ↑ 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
- ↑ J. Sánchez et al, Confinement transitions in TJ-II under Li-coated wall conditions, Nucl. Fusion 49 (2009) 104018
- ↑ F.L. Tabarés, M. Ochando, D. Tafalla, F. Medina, K. McCarthy, J.M. Fontdecaba, M. Liniers, J. Guasp, E. Ascasíbar, T. Estrada, I. Pastor, TJ-II Team, Energy and Particle Balance Studies Under Full Boron and Lithium-Coated Walls in TJ-II, Contrib. Plasma Phys. 50, 6-7 (2010) 610–615