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Separatrix: Difference between revisions
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A separatrix is a boundary between domains with distinct dynamical behaviour. | [[File:Geometry.png|400px|thumb|right|Sketch of tokamak geometry, including separatrix]] | ||
A separatrix is a boundary between domains with distinct dynamical behaviour (phase curves) in a dynamical system. | |||
<ref>[http://eom.springer.de/s/s084540.htm Separatrix (Encyclopaedia of Mathematics)]</ref> | <ref>[http://eom.springer.de/s/s084540.htm Separatrix (Encyclopaedia of Mathematics)]</ref> | ||
<ref>[[:Wikipedia: | <ref>[[:Wikipedia:Separatrix_(dynamical_systems)]]</ref> | ||
In the fusion context, the term is used to describe: | In the fusion context, the term refers to the trajectories of the magnetic field lines and is used to describe: | ||
* | * In the case of a [[Divertor|divertor]] configuration in [[Tokamak|tokamaks]], or a similar situation in other devices: the boundary between closed and open field lines, separating the toroidally confined region from the region where field lines connect to material surfaces. In the case of a 'double null' configuration, two separatices can be distinguished: the main (primary) and secondary separatrix. Only the main separatrix truly separates the regions of closed and open field lines. | ||
* | * The boundary between the inside of a [[Magnetic island|magnetic island]] and the surrounding region. | ||
In the case of plasmas that are limited by material objects (limiters or walls), | |||
the use of the term separatrix to describe the boundary between the confined plasma and | |||
the external part of the plasma that connects to the wall (the [[Scrape-Off Layer]], SOL) is not correct. | |||
In this case, the boundary should be referred to as the Last Closed Magnetic Surface (LCMS) or Last Closed Flux Surface (LCFS). | |||
== See also == | |||
* [[Flux surface]] | |||
* [[Connection length]] | |||
== References == | == References == | ||
<references /> | <references /> | ||