  Atomic magnetometry was performed at Earth's magnetic field over a free-space
distance of ten meters. Two laser beams aimed at a distant alkali-vapor cell
excited and detected the $^{87}$Rb magnetic resonance, allowing the magnetic
field within the cell to be interrogated remotely. Operated as a driven
oscillator, the magnetometer measured the geomagnetic field with
\lessgtrsim{\lesssim}3.5\,pT precision in a $\sim$2\,s data acquisition; this
precision was likely limited by ambient field fluctuations. The sensor was also
operated in self-oscillating mode with a 5.3\,pT/$\sqrt{\textrm{Hz}}$ noise
floor. Further optimization will yield a high-bandwidth, fully remote
magnetometer with sub-pT sensitivity.

Atomic Physics;Quantum Physics