INTERSTELLAR MAGNETIC FIELDS OBSERVED BY VOYAGER 1 BEYOND THE HELIOPAUSE

Voyager 1 (V1) was beyond the heliopause between 2013.00 and 2014.41, where it was making in situ observations of the interstellar magnetic field (ISMF). The average azimuthal angle and elevation angle of the magnetic field B were = 292 degrees.5 +/- 1 degrees.4 and = 22.degrees 1 +/- 1 degrees.2, respectively. The angles lambda and delta varied linearly at (1 degrees.4 +/- 0 degrees.1) yr(-1) and (-1 degrees.1 +/- 0 degrees.1) yr(-1), respectively, suggesting that V1 was measuring the draped ISMF around the heliopause. The distributions of hourly averages of lambda and delta were Gaussian distributions, with most probable values 292 degrees.5 and 22 degrees.1, and standard deviations (SDs) 1 degrees.3 and 1 degrees.1, respectively. The small SD indicates little or no turbulence transverse to B. An abrupt decrease in B from 0.50 nT on 2013/129.9 to 0.46 nT on 2013/130.6 was observed, possibly associated with a weak reverse shock or magnetoacoustic pressure wave following a burst of electron plasma oscillations. Between 2013/130.6 and 2013/365.3, < B > = 0.464 +/- 0.009 nT , = 292 degrees.6 +/- 0 degrees.8, and = 22 degrees.1 +/- 1 degrees.1. The corresponding distribution of hourly averages of B was Gaussian with the most probable value 0.464 nT and sigma = 0.009 nT. Since the uncertainty s corresponds to the instrument and digitization noise, these observations provided an upper limit to the turbulence in the ISMF. The distributions of the hourly increments of B were Gaussian distributions with sigma = 0.05 nT, 0 degrees.4, and 0 degrees.4, respectively, indicating that the V1 did not detect evidence of "intermittent bursts" of interstellar turbulence.