Triangularity: Difference between revisions

Revision as of 10:30, 11 June 2014

The triangularity refers to the shape of the poloidal cross section of the Last Closed Flux surface (LCFS) or separatrix of a tokamak. Assuming:

R₀ is the major radius of the midpoint of the 2 intersections of the LCFS or separatrix with the equatorial plane (Z = 0).
a is the minor radius of the plasma, defined as the radial difference between the 2 intersections of the LCFS or separatrix with the equatorial plane (Z = 0), divided by 2.
R_up is the major radius of the upper X-point (in case it exists) or of the highest vertical point of the LCFS.
R_down is the major radius of the lower X-point (in case it exists) or of the lowest vertical point of the LCFS.

The upper triangularity is then defined as follows:

\kappa _{up}=(R_{0}-R_{up})/a

and similar for κ_down. The overall triangularity is defined as the mean of κ_up and κ_down.

@@ Line 2: / Line 2: @@
 Assuming:
 * ''R<sub>0</sub>'' is the major radius of the midpoint of the 2 intersections of the LCFS or separatrix with the equatorial plane (''Z'' = 0).
-* ''a'' is the minor radius of the plasma, defined as the difference of the 2 intersections of the LCFS or separatrix with the equatorial plane (''Z'' = 0), divided by 2.
+* ''a'' is the minor radius of the plasma, defined as the radial difference between the 2 intersections of the LCFS or separatrix with the equatorial plane (''Z'' = 0), divided by 2.
 * ''R<sub>up</sub>'' is the major radius of the upper X-point (in case it exists) or of the highest vertical point of the LCFS.
 * ''R<sub>down</sub>'' is the major radius of the lower X-point (in case it exists) or of the lowest vertical point of the LCFS.