Jim Fuller edited Magnetic Constraints.tex  about 9 years ago

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\end{equation}  with the $H$ subscript indicating the right hand side of equation \ref{eqn:BHburn} should be evaluated near the H-burning shell where $B_c$ is minimized.   Figure \ref{fig:DipoleBEvol} shows the value of $B_c(r_H)$ for dipole modes as a function of stellar radius for an evolving star with $M=1.5M_\odot$. At the lower subgiant branch, where the stellar radius is $R\sim 3 R_\odot$, field strengths near $B_c \sim 10^7 \, {\rm G}$ are required for magnetic suppression. As the star evolves up the red giant branch, the value of $B_c$ decreases sharply as the value of $r_H$ decreases and $N_H$ increases. By the bump, field strengths of under $10^4 \, {\rm G}$ are sufficient for magnetic suppression. At the clump, field strengths of $\sim \! 3 \times $10^{4} 10^{4}  \, {\rm G}$ are sufficient. As discussed above, these field strengths are easily attainable for the descendants of magnetic Ap stars. Magnetic suppression on the early sub-giant branch is likely to be less common due to the higher field strengths required.