ROBUSTNESS OF TRUNCATED ALPHA-OMEGA DYNAMOS WITH A DYNAMIC ALPHA

In a recent work (Covas et al., 1996), the behaviour and the robustnes s of truncated alpha Omega dynamos with a dynamic alpha were studied w ith respect to a number of changes in the driving term of the dynamic alpha equation, which was considered previously by Schmalz and Stir (1 991) to be of the form similar to A phi B phi Here we review and exten d our previous work and consider the effect of adding a quadratic quen ching term of the form alpha\B\(2). We find that, as before, such a ch ange can have significant effects on the dynamics of the related trunc ated systems. We also find intervals of(negative) dynamo numbers, in t he system considered by Schmalz and Stix (1991), for which there is se nsitivity with respect to small changes in the dynamo number and the i nitial conditions, similar to what was found in our previous work. Thi s latter behaviour may be of importance in producing the intermittent type of behaviour observed in the Sun.