Voyager 1 Observations of the Local Interstellar Magnetic Field

Voyager 1 (V1) has been observing interstellar magnetic fields throughout 2013. The azimuthal and elevation angles of the hour averages of the magnetic field were constant at λ = 292° and δ = 22°, respectively, with a uncertainty of approximately 1°. The magnetic field strength B was decreasing slowly until day 129.5, 2013, when it dropped abruptly by a small but significant amount, and then remained uniform from day 129.5 through day 365.3, 2013 with an average value 0.46 ± 0.01 nT. The distributions of B, λ and δ were Gaussian. The Gaussian fit gives the most probable value of B = 0.464 ± 0.005 nT; the uncertainty can be attributed to the instrument noise and digitization level. The distributions of hourly increments of the magnetic field are also very accurately described by a Gaussian distribution. The standard deviation of the hourly increments of B, λ and δ are 0.006 ± 0.001 nT, -0.003° ± 0.007° and -0.004° ± 0.003°. These results set upper limits on the interstellar turbulence.