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The rate at which the solar wind extracts angular momentum from the Sun hasbeen predicted by theoretical models for many decades, and yet we lack aconclusive measurement from in-situ observations. In this letter we present anew estimate of the time-varying angular momentum flux in the equatorial solarwind, as observed by the \textit{Wind} spacecraft from 1994-2019. We separatethe angular momentum flux into contributions from the protons, alpha particles,and magnetic stresses, showing that the mechanical flux in the protons is$\sim$3 times larger than the magnetic field stresses. We observe the tendencyfor the angular momentum flux of fast wind streams to be oppositely signed tothe slow wind streams, as noted by previous authors. From the average totalflux, we estimate the global angular momentum loss rate of the Sun to be$3.3\times10^{30}$erg, which lies within the range of various MHD wind modelsin the literature. This angular momentum loss rate is a factor of $\sim$2weaker than required for a Skumanich-like rotation period evolution($\Omega_*\propto $ stellar age$^{-1/2}$), which should be considered instudies of the rotation period evolution of Sun-like stars.

Direct Detection of Solar Angular Momentum Loss with the Wind Spacecraft