NEUTRAL LINE CHAOS AND PHASE-SPACE STRUCTURE

Numerical surface of section techniques and analytic methods are used to study phase space structure and chaos near a neutral line. We find that, for -(2h)1/2 less-than-or-equal-to P(y) less-than-or-equal-to (2h)1/2, the ratio of fields, b(n), rather than kappa, is the appropriate chaos parameter, where P(y) and h are the normalized canonical momentum and energy. We find that the action integral adiabatic constant is approximately conserved and can be used to describe particle motion as long as b(n) << 1 or b(n) >> 1.