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TJ-II:Magnetics: Difference between revisions
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== Mirnov coils == | == Mirnov coils == | ||
[[File: | [[File:Mirnov_coils.png|600px|thumb|right|The poloidal array of Mirnov coils at TJ-II]] | ||
TJ-II is fitted with an ample set of Mirnov coils: | [[TJ-II]] is fitted with an ample set of Mirnov coils: | ||
<ref>[http://www.new.ans.org/pubs/journals/fst/a_1283 R. Jiménez-Gómez | <ref>E. Ascasíbar et al, ''Energy content and magnetic configuration scan in TJ-II plasmas'', [http://www-fusion.ciemat.es/SW2005/conferences/madison99/Papers/Ascsibar.pdf 12<sup>th</sup> Int. Stell. Workshop (1999)]</ref> | ||
<ref>R. Jiménez-Gómez et al., ''Analysis of Magnetohydrodynamic Instabilities in TJ-II Plasmas'', [http://www.new.ans.org/pubs/journals/fst/a_1283 Fusion Science and Technology '''51''', 20 (2007)]</ref> | |||
* One poloidal array with 15 coils measuring the poloidal field component. This array is located between [[TJ-II:Sectors|sectors]] D4 and D5, at ''φ'' = | <ref>R. Jiménez-Gómez, A. Könies, E. Ascasíbar, F. Castejón, T. Estrada, L. G. Eliseev, A. V. Melnikov, J.A. Jiménez, D. G. Pretty, D. Jiménez-Rey, M.A. Pedrosa, A. de Bustos and S. Yamamoto, ''Alfvén eigenmodes measured in the TJ-II stellarator'', [[doi:10.1088/0029-5515/51/3/033001|Nucl. Fusion '''51''', 3 (2011) 033001]]</ref> | ||
There are two straight arrays above the plasma column, each with 12 coils, mounted in a 0.5 mm thick stainless steel tube attached to a port flange. The 12 coils are distributed in 4 groups of 3 coils each, separated by a distance of 30 mm. The three coils in each group measure the three cylindrical components (''R'', ''φ'', and ''Z'') of the magnetic field. | |||
* One straight array in [[TJ-II:Sectors|sector]] B5, at ''φ'' = 232°. The corresponding signals in the [[TJ-II:Shot database|TJ-II database]] are called 'MIB5xy', where 'x' is 'R', 'F' (φ), or 'Z', and 'y' is the coil number. | |||
* One straight array in [[TJ-II:Sectors|sector]] C4, at ''φ'' = 308°. | |||
* One poloidal array with 15 coils measuring the poloidal field component. This array is located between [[TJ-II:Sectors|sectors]] D4 and D5, at ''φ'' = 45°. The signals in the [[TJ-II:Shot database|TJ-II database]] corresponding to these coils are called 'MID5Px', where 'x' is the coil number. This array has been enhanced by 10 additional coils (5 at each end). | |||
* Two toroidal arrays (installed 2018) <ref>E. Ascasíbar et al., ''Measurements of magnetic field fluctuations in TJ-II plasmas with new in-vessel helical arrays of magnetic coils'', [[doi:10.1063/5.0102037|Rev. Sci. Instrum. '''93''' (2022) 093508]]</ref> | |||
== Rogowski coils == | == Rogowski coils == | ||
Two Rogowski coils have been installed in [[TJ-II:Sectors|sectors]] A5 (148.7°) and B4 (211.3°). Since the coils have to surround the plasma column completely, they are located under the protecting tiles of the groove that runs toroidally all along the [[TJ-II:Vacuum system|vacuum vessel]]. For this purpose, 2 mm deep channels were machined on the vacuum side of the groove, at the above mentioned poloidal cross sections, in order to allow enough space for the coils. | |||
The signals 'Ip_a5_' and 'Ip_b4_' in the [[TJ-II:Shot database|TJ-II database]] provide the corresponding measurements of the net plasma current (in kA). | |||
== Diamagnetic loops == | == Diamagnetic loops == | ||
[[File:TJ-II_Diamagnetic_loop.jpg|200px|thumb|left|TJ-II diamagnetic loop]] | [[File:TJ-II_Diamagnetic_loop.jpg|200px|thumb|left|TJ-II diamagnetic loop of [[TJ-II:Sectors|sector]] B4]] | ||
Two internal diamagnetic loops are installed | Two internal diamagnetic loops are installed in [[TJ-II:Sectors|sector]] A5 (135°) and B4 (225°). | ||
They consist of a main loop which encircles the plasma column | They consist of a main loop which encircles the plasma column | ||
and runs under the protecting tiles in the groove region and a compensating loop which | and runs under the protecting tiles in the groove region and a compensating loop which | ||
measures only the vacuum magnetic flux. | measures only the vacuum magnetic flux. | ||
The signals 'W_a5_corr_' and 'W_b4_corr_' in the [[TJ-II:Shot database|TJ-II database]] return the energy content of the plasma (in kJ), based on the diamagnetic loop in [[TJ-II:Sectors|sectors]] A5 and B4, corrected for the net plasma current. | |||
== References == | == References == | ||
<references /> | <references /> | ||