Quasihelically symmetric stellarators are nonaxisymmetric, toroidal configurations in which the strength of the magnetic field depends on only one angular coordinate, instead of two, within the constant pressure surfaces. The confinement properties of these configurations are similar to those of axisymmetric tokamaks. Although stellarators with exact quasihelical symmetry are proven not to exist, good approximations can be found.

The confinement and stability properties of toroidal plasma equilibria are largely determined by the strength of the magnetic field expressed in terms of Boozer coordinates. Constraints due to the toroidicity of the configuration and the divergence-free property of the magnetic field limit the freedom in the Taylor series expansion of the magnetic field strength. Such field strength constraints limit the variety of desirable three-dimensional plasma equilibria that are available to the fusion program.

This paper investigates the optimization of both single and full polarization radar transmission waveforms to maximize target identification discrimination. This theory is applied to the discrimination of the T-72 and Ml battle tanks based upon simulated target frequency response data. Significant performance improvement in identification is obtained using an optimized transmission waveform over that of a standard chirped pulse. generated using the Fast Illinois Solver Code Q^ISC) that applies a method-of-moments technique to provide high fidelity at relatively low radar frequencies. The specific VHF-band data generated by S AIC-Champaign cover frequencies between 225-375 MHz at an aspect interval of 2°.