  In designing stellarators, any design decision ultimately comes with a
trade-off. Improvements in particle confinement, for instance, may increase the
burden on engineers to build more complex coils, and the tightening of
financial constraints may simplify the design and worsen some aspects of
transport. Understanding trade-offs in stellarator designs is critical in
designing high performance devices that satisfy the multitude of physical,
engineering, and financial criteria. In this study we show how multi-objective
optimization (MOO) can be used to investigate trade-offs and develop insight
into the role of design parameters. We discuss the basics of MOO, as well as
practical solution methods for solving MOO problems. We apply these methods to
bring insight into the selection of two common design parameters: the aspect
ratio of an ideal magnetohydrodynamic equilibrium, and the total length of the
electromagnetic coils.
