Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Passive Probe for Subsurface Oceans and Liquid Water in Jupiter's Icy
  Moons   We describe an interferometric reflectometer method for passive detection of
subsurface oceans and liquid water in Jovian icy moons using Jupiter's
decametric radio emission (DAM). The DAM flux density exceeds 3,000 times the
galactic background in the neighborhood of the Jovian icy moons, providing a
signal that could be used for passive radio sounding. An instrument located
between the icy moon and Jupiter could sample the DAM emission along with its
echoes reflected in the ice layer of the target moon. Cross-correlating the
direct emission with the echoes would provide a measurement of the ice shell
thickness along with its dielectric properties. The interferometric
reflectometer provides a simple solution to sub-Jovian radio sounding of ice
shells that is complementary to ice penetrating radar measurements better
suited to measurements in the anti-Jovian hemisphere that shadows Jupiter's
strong decametric emission. The passive nature of this technique also serves as
risk reduction in case of radar transmitter failure. The interferometric
reflectometer could operate with electrically short antennas, thus extending
ice depth measurements to lower frequencies, and potentially providing a deeper
view into the ice shells of Jovian moons.

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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: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-lat
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: nlin
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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom