Dewar, RobertCuthbert, PBall, Rowena2009-10-272010-12-202009-10-272010-12-20Physical Review Letters 86.11 (2001): 2321-23240031-90071079-7114http://hdl.handle.net/10440/971http://digitalcollections.anu.edu.au/handle/10440/971The spectrum of ideal magnetohydrodynamic (MHD) pressure-driven (ballooning) modes in strongly nonaxisymmetric toroidal systems is difficult to analyze numerically owing to the singular nature of ideal MHD caused by lack of an inherent scale length. In this paper, ideal MHD is regularized by using a k-space cutoff, making the ray tracing for the WKB ballooning formalism a chaotic Hamiltonian billiard problem. The minimum width of the toroidal Fourier spectrum needed for resolving toroidally localized ballooning modes with a global eigenvalue code is estimated from the Weyl formula. This phase-space-volume estimation method is applied to two stellarator cases.4 pageshttp://www.sherpa.ac.uk/romeo/index.php "Author can archive pre-print (ie pre-refereeing) … post-print (ie final draft post-refereeing) … [and] publisher's version/PDF. Link to publisher version … [and] Copyright notice required. Publisher's version/PDF can be used on … employers web site." - from SHERPA/RoMEO site (as at 25/02/10). ©2001 The American Physical SocietyKeywords: Chaos theory; Eigenvalues and eigenfunctions; Estimation; Fourier transform infrared spectroscopy; Hamiltonians; Magnetohydrodynamics; Phase space methods; Quantum optics; Global ballooning; Quantum chaos; Magnetoplasma200110.1103/PhysRevLett.86.23212015-12-08