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Toroidal coordinates: Difference between revisions
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All of the above coordinate systems are ''fixed'' and ''axisymmetric'' (except the Cartesian system). | All of the above coordinate systems are ''fixed'' and ''axisymmetric'' (except the Cartesian system). | ||
By contrast, magnetic coordinates ''adapt'' to the magnetic field, and therefore to the [[MHD equilibrium]] (also see [[Flux surface]]). Magnetic coordinates simplify the description of the magnetic field. | By contrast, magnetic coordinates ''adapt'' to the magnetic field, and therefore to the [[MHD equilibrium]] (also see [[Flux surface]]). | ||
Magnetic coordinates simplify the description of the magnetic field. | |||
In 3 dimensions (not assuming axisymmetry), the most commonly used coordinate systems are: | |||
* Hamada coordinates. <ref>S. Hamada, Nucl. Fusion '''2''' (1962) 23</ref><ref>[http://dx.doi.org/10.1063/1.1706651 J.M. Greene and J.L Johnson, ''Stability Criterion for Arbitrary Hydromagnetic Equilibria'', Phys. Fluids '''5''' (1962) 510]</ref> In these coordinates, both the field lines and current lines corresponding to the [[MHD equilibrium]] are straight. | * Hamada coordinates. <ref>S. Hamada, Nucl. Fusion '''2''' (1962) 23</ref><ref>[http://dx.doi.org/10.1063/1.1706651 J.M. Greene and J.L Johnson, ''Stability Criterion for Arbitrary Hydromagnetic Equilibria'', Phys. Fluids '''5''' (1962) 510]</ref> In these coordinates, both the field lines and current lines corresponding to the [[MHD equilibrium]] are straight. | ||
* Boozer coordinates. <ref>[http://dx.doi.org/10.1063/1.863297 A.H. Boozer, ''Plasma equilibrium with rational magnetic surfaces'', Phys. Fluids '''24''' (1981) 1999]</ref><ref>[http://dx.doi.org/10.1063/1.863765 A.H. Boozer, ''Establishment of magnetic coordinates for a given magnetic field'', Phys. Fluids '''25''' (1982) 520]</ref> In these coordinates, the field lines corresponding to the [[MHD equilibrium]] are straight. | * Boozer coordinates. <ref>[http://dx.doi.org/10.1063/1.863297 A.H. Boozer, ''Plasma equilibrium with rational magnetic surfaces'', Phys. Fluids '''24''' (1981) 1999]</ref><ref>[http://dx.doi.org/10.1063/1.863765 A.H. Boozer, ''Establishment of magnetic coordinates for a given magnetic field'', Phys. Fluids '''25''' (1982) 520]</ref> In these coordinates, the field lines corresponding to the [[MHD equilibrium]] are straight. | ||
These coordinate systems are related. | These two coordinate systems are related. | ||
<ref>K. Miyamoto, ''Controlled fusion and plasma physics'', Vol. 21 of Series in | <ref>K. Miyamoto, ''Controlled fusion and plasma physics'', Vol. 21 of Series in | ||
Plasma Physics, CRC Press (2007) ISBN 1584887095</ref> | Plasma Physics, CRC Press (2007) ISBN 1584887095</ref> | ||