Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing the inner boundaries of Saturn's A ring with the Iapetus -1:0
  nodal bending wave   The Iapetus -1:0 nodal bending wave, the first spiral wave ever described in
Saturn's rings, has been seen again for the first time in 29 years. We
demonstrate that it is in fact the nodal bending wave, not the 1:0 apsidal
density wave as previously reported. We use wavelet analysis to determine the
wavelength profile, thus deriving the surface density at every point in the
region covered by the bending wave. This profile is consistent with surface
densities measured from more localized spiral density waves in the outer
Cassini Division and the inner and mid-A Ring, varying smoothly from the low
values of the former to the higher values of the latter.
  Most remarkably, our analysis indicates that there is no significant change
in surface density across the boundary between the outer Cassini Division and
the inner-A ring, despite the very abrupt increase in optical depth and
reflected brightness at this location. We consider anew the nature of the
classically identified "inner edge of the A ring," given that it does not
appear to be correlated with any abrupt increase in surface density. There is
an abrupt increase in surface density at the Pandora 5:4 density wave, ~300 km
outward of the A ring's inner edge. Further study is needed to robustly
interpret our findings in terms of particle properties and abundances, much
less to explain the origins of the implied structure.

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The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: math
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat