TITLE
	Reduction of Chaos in Hamiltonian Systems

AUTHOR
	John CARY

ABSTRACT
	The operation of many physical devices, including accelerators and plasma confinement 
	devices, is improved when these systems are integrable.  Then, the trajectories are 
	regular, well confined, and predictable.  Unfortunately, nonintegrable systems appear 
	to be generic.  Early stellarators (one type of magnetic plasma confinement system) 
	had very large islands and chaotic regions, and this was considered to limit their 
	performance.  The dynamic aperture (region of confined trajectories) of accelerators 
	is limited by chaotic effects.  The problem occurs because one cannot simply pick a 
	Hamiltonian.  The system must satisfy non dynamical constraints.  For example, focusing 
	magnetic fields in accelerators must be both divergence and curl free. The magnetic 
	field in a plasma confinement device is determined by the plasma itself.  This talk 
	focuses on how one can find Hamiltonians (and, hence, good physical systems) with 
	reduced chaos yet satisfying the physical constraints.  The resulting systems have 
	improved performance - in some cases allowing new physical regimes to work at all.