Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Helioseismic inversion to infer depth profile of solar meridional flow
  using spherical Born kernels   Accurate inference of solar meridional flow is of crucial importance for the
understanding of solar dynamo process. Wave travel times, as measured on the
surface, will change if the waves encounter perturbations e.g. in the sound
speed or flows, as they propagate through the solar interior. Using functions
called sensitivity kernels, we may image the underlying anomalies that cause
measured shifts in travel times. The inference of large-scale structures e.g
meridional circulation requires computing sensitivity kernels in spherical
geometry. Mandal et al. (2017) have computed such spherical kernels in the
limit of the first-Born approximation. In this work, we perform an inversion
for meridional circulation using travel-time measurements obtained from 6 years
of SDO/HMI data and those sensitivity kernels. We enforce mass conservation by
inverting for a stream function. The number of free parameters is reduced by
projecting the solution on to cubic B-splines in radius and derivatives of the
Legendre-polynomial basis in latitude, thereby improving the condition number
of the inverse problem. We validate our approach for synthetic observations
before performing the actual inversion. The inversion suggests a single-cell
profile with the return-flow occurring at depths below 0.78 $R_\odot$.

15
The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: cond-mat
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The categories of this paper are: q-alg