Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Features of magnetic field switchbacks in relation to the local-field
  geometry of large-amplitude Alfv\'enic oscillations: \emph{Wind} and
  \emph{PSP} observations   In this letter we report observations of magnetic switchback (SB) features
near 1 au using data from the \emph{Wind} spacecraft. These features appear to
be strikingly similar to the ones observed by the Parker Solar Probe mission
(PSP) closer to the Sun: namely, one-sided spikes (or enhancements) in the
solar-wind bulk speed $V$ that correlate/anti-correlate with the spikes seen in
the radial-field component $B_R$. In the solar-wind streams that we analyzed,
these specific SB features near 1 au are associated with large-amplitude
Alfv\'enic oscillations that propagate outward from the sun along a local
background (prevalent) magnetic field $\bf{B}_0$ that is nearly radial. We also
show that, when $\bf{B}_0$ is nearly perpendicular to the radial direction, the
large amplitude Alfv\'enic oscillations display variations in $V$ that are
two-sided (i.e., $V$ alternately increases and decreases depending on the
vector $\Delta\bf{B}=\bf{B} - \bf{B}_0$). As a consequence, SBs may not appear
always as one-sided spikes in $V$, especially at larger heliocentric distances
where the local background field statistically departs from the radial
direction. We suggest that SBs can be well described by large-amplitude
Alfv\'enic fluctuations if the field rotation is computed with respect to a
well-determined local background field that, in some cases, may deviate from
the large-scale Parker field.

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The categories of this paper are: cs
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The categories of this paper are: acc-phys
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The categories of this paper are: math
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: cond-mat