TJ-II:Magnetic coordinates: Difference between revisions

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# [[Toroidal coordinates|Cylindrical]] <math>(R, \phi, Z)</math>, where <math>R^2 = X^2 + Y^2</math> and <math>\tan \phi = Y/X</math>.

In order to make comparisons between diagnostics, it is useful to convert these real-space coordinates to flux coordinates. This coordinate transform depends on the particular magnetic configuration used in a given experiment. Two tools are available to do so ([http://www-fusion.ciemat.es/cgi-bin/dir/dirnew.cgi?manuals/geometry_TJII/ See the on-line documentation] - only internal laboratory access):

In order to make comparisons between diagnostics, it is useful to convert these real-space coordinates to [[flux coordinates]]. This coordinate transform depends on the particular magnetic configuration used in a given experiment. Two tools are available to do so ([http://www-fusion.ciemat.es/cgi-bin/dir/dirnew.cgi?manuals/geometry_TJII/ See the on-line documentation] - only internal laboratory access):

First, vacuum equilibrium calculations from [[VMEC]]. These are then used to obtain magnetic flux coordinates <math>(\psi, \theta, \phi)</math>. A set of routines is available to perform the corresponding coordinate transforms.<ref>[[File:TJ2 Library V2.pdf]]: TJ-II Library Manual, Informe Técnico del CIEMAT Nº 963</ref> The drawback of the VMEC calculations is (a) that magnetic islands are ignored, and (b) that only a limited number of configurations is available.

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 # [[Toroidal coordinates|Cylindrical]] <math>(R, \phi, Z)</math>, where <math>R^2 = X^2 + Y^2</math> and <math>\tan \phi = Y/X</math>.
-In order to make comparisons between diagnostics, it is useful to convert these real-space coordinates to flux coordinates. This coordinate transform depends on the particular magnetic configuration used in a given experiment. Two tools are available to do so ([http://www-fusion.ciemat.es/cgi-bin/dir/dirnew.cgi?manuals/geometry_TJII/ See the on-line documentation] - only internal laboratory access):
+In order to make comparisons between diagnostics, it is useful to convert these real-space coordinates to [[flux coordinates]]. This coordinate transform depends on the particular magnetic configuration used in a given experiment. Two tools are available to do so ([http://www-fusion.ciemat.es/cgi-bin/dir/dirnew.cgi?manuals/geometry_TJII/ See the on-line documentation] - only internal laboratory access):
 First, vacuum equilibrium calculations from [[VMEC]]. These are then used to obtain magnetic flux coordinates <math>(\psi, \theta, \phi)</math>. A set of routines is available to perform the corresponding coordinate transforms.<ref>[[File:TJ2 Library V2.pdf]]: TJ-II Library Manual, Informe Técnico del CIEMAT Nº 963</ref> The drawback of the VMEC calculations is (a) that magnetic islands are ignored, and (b) that only a limited number of configurations is available.