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In this letter we report observations of magnetic switchback (SB) featuresnear 1 au using data from the \emph{Wind} spacecraft. These features appear tobe strikingly similar to the ones observed by the Parker Solar Probe mission(PSP) closer to the Sun: namely, one-sided spikes (or enhancements) in thesolar-wind bulk speed $V$ that correlate/anti-correlate with the spikes seen inthe radial-field component $B_R$. In the solar-wind streams that we analyzed,these specific SB features near 1 au are associated with large-amplitudeAlfv\'enic oscillations that propagate outward from the sun along a localbackground (prevalent) magnetic field $\bf{B}_0$ that is nearly radial. We alsoshow that, when $\bf{B}_0$ is nearly perpendicular to the radial direction, thelarge amplitude Alfv\'enic oscillations display variations in $V$ that aretwo-sided (i.e., $V$ alternately increases and decreases depending on thevector $\Delta\bf{B}=\bf{B} - \bf{B}_0$). As a consequence, SBs may not appearalways as one-sided spikes in $V$, especially at larger heliocentric distanceswhere the local background field statistically departs from the radialdirection. We suggest that SBs can be well described by large-amplitudeAlfv\'enic fluctuations if the field rotation is computed with respect to awell-determined local background field that, in some cases, may deviate fromthe large-scale Parker field.

the astrophysical journal. letters

Features of magnetic field switchbacks in relation to the local-field  geometry of large-amplitude Alfv\'enic oscillations: \emph{Wind} and  \emph{PSP} observations