Jim Fuller edited WH_YIS_THIS_PARA_WIDER__.tex  almost 9 years ago

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Turning to higher masses, we see that for a given \numax\, stars above 1.4\msol\ require increasingly strong magnetic fields to suppress their dipole modes. From Figure 4, there is no clear upper limit to the field strengths attainable in red giant cores, given that suppressed stars are common even when field strengths $ B> 1 \, {\rm MG}$ are required for suppression. However, the hint of a decline in the occurrence of dipole-suppressed stars above 2\msol\ seen in Fig. 3 suggests there may be a mass above which dynamo-generated magnetic fields can no longer cause oscillation mode suppression in intermediate-mass stars.  %Such a cutoff might be caused by the different core structure of stars more massive than 2\msol, which evolve through the red giant phase much faster than stars of lower mass.   [THIS PARA SEEMS TO BE REPEATING WHAT WAS SAID 4 AND 5 PARAs AGO]  The high occurrence rate of dipole mode suppression demonstrates that core-dynamo-generated fields can remain through the red giant phase, more than $10^8 \, {\rm yr}$ after the dynamo shuts off at the end of hydrogen-core burning. Therefore, dynamo-generated fields are frequently able to settle into long-lived stable configurations \citep{Braithwaite_2004,Braithwaite_2006,Duez_2010}, a result that was not certain from magnetohydrodynamical simulations.  The occurrence rate of these long-lived core fields is much larger than the occurrence rate of strong fields observed at the surfaces of magnetic A stars, which may have been generated by a pre-hydrogen-core burning dynamo during star formation (e.g., \citealt{Moss_2004}). We conclude that fields generated during hydrogen-core burning are able to settle into stable equilibrium configurations much more commonly (greater than $60\%$ of the time) than fields generated during star formation (less than $10\%$ of the time).