Design studies of low aspect ratio quasi-omnigenous stellarators

Significant progress has been made in the development of new, compact stellarator devices that could test optimization principles for the design of a more attractive reactor. These are 3 and 4 field period low aspect ratio quasi-omnigenous stellarators based on an optimization method that aims at improved confinement, stability, ease of coil design, low aspect ratio and low bootstrap current. With respect to the analysis of these devices, the authors have developed improved measures of neoclassical transport, collisionless loss analyses of ICRF tail and ct population confinement and methods for the rapid assessment of ballooning stability boundaries.