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Despite rapid progress in the discovery and characterization of surface magnetic fields, very little is known about internal stellar magnetic fields. This has prevented the development of a coherent picture of stellar magnetism; for example it is not clear if some of the magnetic flux observed at the surface of main sequence stars can be conserved through the various phases of stellar evolution and be responsible for the existence of strongly magnetized compact remnants (magnetic white dwarfs and neutron stars \citep{Wickramasinghe_2000,Duncan_1992}).  After exhausting hydrogen in their cores, most main sequence stars evolve to become red giants. During this phase the stellar structure is characterized by an expanding convective envelope and a contracting radiative core. Acoustic waves (p modes) excited by turbulent surface  convection can couple to gravity waves (g modes) in the cores. Consequently, non-radial modes become mixed modes that contain significant inertia in both the envelope (the p mode cavity) and the core (the g mode cavity). % Acoustic waves excited by turbulent convection in the envelope can propagate through the star and be used to %probe the stellar interiors. Asteroseismology of thousands of red giants has just become possible thanks to the %space satellites CoRoT and Kepler. During the red giant branch (RGB) the frequency of stochastically generated %acoustic waves (p-modes) becomes comparable to the frequency of internal gravity waves (g-modes) in the radiative %core of the star. In this situation a crosstalk between p-modes and g-modes becomes possible if enough energy can %leak through the evanescent region, which is located between the acoustic cavity and the gravity-waves cavity and %which extent depends on the harmonic degree ($\ell$) of the mode.  %This gives rise to standing waves with a mixed nature (mixed modes). The restoring force for these waves is the %pressure gradient in the envelope and gravity in the core.