Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Torsional Alfv\'en resonances as an efficient damping mechanism for
  non-radial oscillations in red giant stars   Stars are self-gravitating fluids in which pressure, buoyancy, rotation and
magnetic fields provide the restoring forces for global modes of oscillation.
Pressure and buoyancy energetically dominate, while rotation and magnetism are
generally assumed to be weak perturbations and often ignored. However,
observations of anomalously weak dipole mode amplitudes in red giant stars
suggest that a substantial fraction of these are subject to an additional
source of damping localised to their core region, with indirect evidence
pointing to the role of a deeply buried magnetic field. It is also known that
in many instances the gravity-mode character of affected modes is preserved,
but so far no effective damping mechanism has been proposed that accommodates
this aspect. Here we present such a mechanism, which damps the oscillations of
stars harbouring magnetised cores via resonant interactions with standing
Alfv\'en modes of high harmonic index. The damping rates produced by this
mechanism are quantitatively on par with those associated with turbulent
convection, and in the range required to explain observations, for realistic
stellar models and magnetic field strengths. Our results suggest that magnetic
fields can provide an efficient means of damping stellar oscillations without
needing to disrupt the internal structure of the modes, and lay the groundwork
for an extension of the theory of global stellar oscillations that incorporates
these effects.

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The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph