Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Common Coil Dipole for High Field Magnet Design and R&D   The common coil geometry provides an alternate design to the conventional
cosine theta dipoles. It allows a wider range of conductor and magnet
technologies. It also facilitates a low-cost, rapid-turn-around design and R&D
program. Recent studies carried out as a part of the US Magnet Development
Program revealed that at high fields (20 T with 15% operating margin or more),
the common coil design also uses significantly less conductor (particularly
much less HTS), as compared to that in the other designs.

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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
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The categories of this paper are: math
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The categories of this paper are: q-fin
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The categories of this paper are: patt-sol
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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
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The categories of this paper are: econ
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph