Jim Fuller edited Discussion.tex  almost 9 years ago

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We have demonstrated that strong magnetic fields in the cores of red giants create a greenhouse effect, trapping mode energy within the core and suppressing mode visibility at the surface. Dipole ($\ell=1$) modes are most sensitive to the core and therefore are affected the most. We predict that $\ell=0$ modes in suppressed oscillators will be unaffected (since they do not propagate within the core), while $\ell=2$ modes will be slightly suppressed, and $\ell=3$ modes should exhibit very little suppression.  The magnetic greenhouse mechanism that operates in suppressed dipole oscillators is unrelated to the suppression of solar-like oscillations in stars exhibiting surface magnetic activity \citep{Chaplin_2011}. In the latter case, the suppression likely arises from magnetic  inhibition of convective motions and suppresses the amplitudes of all oscillation modes, not just the dipole modes. For perfect wave trapping in the core, purely dipole modes only exist in the envelope, with part of their energy leaking into the core as running magneto-gravity waves. If some wave energy does escape the core, it may leave a signature in the form of mixed magneto-gravity acoustic modes which could be used to constrain the internal magnetic field geometry.  %Hence, mixed modes in the usual sense do not exist in stars with suppressed dipole modes.