# Quasisymmetry

From FusionWiki

Quasisymmetric (quasihelically symmetric) plasma equilibria are non-axisymmetric configurations in which the magnetic field strength depends only on one angular coordinate within the magnetic flux surfaces.
^{[1]}
This concept is part of the program of stellarator optimization (designing stellarators to have reduced transport, i.e., heat and particle losses).
^{[2]}

Types of quasisymmetry:

- Quasihelical (QH) symmetry, on which the design of the HSX stellarator (operational) is based.
^{[3]} - Quasipoloidal (QP) symmetry, on which the design of the QPS stellarator (under construction) is based.
^{[4]} - Quasi-axisymmetry (QA), on which the design of the NCSX stellarator was based
^{[5]}

## See also

## References

- ↑ D.A. Garren and A.H. Boozer,
*Existence of quasihelically symmetric stellarators*, Phys. Fluids B 3 (1991) 2822 - ↑ Iván Calvo et al,
*Stellarators close to quasisymmetry*, Plasma Phys. Control. Fusion**55**(2013) 125014 - ↑ J.N. Talmadge, F.S.B. Anderson, D.T. Anderson, C. Deng, W. Guttenfelder, K.M. Likin, J. Lore, J.C. Schmitt, K. Zhai,
*Experimental Tests of Quasisymmetry in HSX*, Plasma and Fusion Research**3**(2008) S1002 - ↑ D.A. Spong, S.P. Hirshman, J.F. Lyon, L.A. Berry and D.J. Strickler,
*Recent advances in quasi-poloidal stellarator physics issues*, Nucl. Fusion**45**(2005) 918 - ↑ M.Yu. Isaev et al,
*The pseudo-symmetric optimization of the National Compact Stellarator Experiment*, Phys. Plasmas**6**, 8 (1999) 3174