QUASR#

Note

The QUASR interface requires simsopt to be installed.

The QUAsi-symmetric Stellarator Repository QUASR [1] [2] [3] is a database of curl-free stellarators optimized for volume quasi-symmetry.

A QUASR configuration can be loaded with

pygvec load-quasr ID

where ID is replaced with the desired configuration. Alternatively

pygvec load-quasr -s FILE

can be used instead, to load a boundary from a simsopt compatible JSON file (e.g. manually downloaded from QUASR). With

pygvec load-quasr -f FILE

the cartesian boundary data is read directly from the supplied netCDF file (in this case simsopt is also not required).

This script will download the requested QUASR configuration, generate a G-Frame [4] to be used as \(h\)-map and the boundary representation in that G-Frame, as well as a GVEC parameter file.

The --tol parameter sets the desired tolerance of the boundary representation which directly impacts the necessary degrees of freedom and therefore computational speed. The --nt and --nz parameters set the number of points in \(\vartheta\) and \(\zeta\) respectively for one field period, from which a G-Frame as well as the boundary cross-sections are computed. The points exclude the periodic point and should be chosen to be odd. With --save-xyz the cartesian boundary data can be saved as a netCDF file. Other parameters can be seen with pygvec load-quasr --help.