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The Sun and Sun-like stars lose angular momentum to their magnetised stellarwinds. This braking torque is coupled to the stellar magnetic field, such thatchanges in the strength and/or geometry of the field modifies the efficiency ofthis process. Since the space-age, we have been able to directly measure solarwind properties using in-situ spacecraft. Furthermore, indirect proxies such assunspot number, geomagnetic indices, and cosmogenic radionuclides, constrainthe variation of solar wind properties on centennial, and millennialtimescales. We use near-Earth measurements of the solar wind plasma andmagnetic field to calculate the torque on the Sun throughout the space-age.Then, reconstructions of the solar open magnetic flux are used to estimate thetime-varying braking torque during the last nine millennia. We assume arelationship for the solar mass loss rate based on observations during thespace-age which, due to the weak dependence of the torque on mass loss rate,does not strongly affect our predicted torque. The average torque during thelast nine millennia is found to be $2.2\times10^{30}$erg, which is comparableto the average value from the last two decades. Our dataset includes grandminima (such as the Maunder Minimum), and maxima in solar activity, where thetorque varies from $\sim1-5\times10^{30}$erg (averaged on decadal timescales),respectively. We find no evidence for any secular variation of the torque ontimescales of less than $9000$ years.

Solar Angular Momentum Loss Over the Past Several Millennia