Counterstreaming electrons in magnetic clouds near 5 AU

Suprathermal electron pitch angle spectrograms were searched for counterstreaming signatures in 31 magnetic clouds identified in Ulysses data when the spacecraft was located similar to5 AU from the Sun. Under the assumption that counterstreaming indicates closed field lines, that is, field lines attached to the Sun at both ends, we find that the clouds range from 0 to 100% closed, with an average of 55% closed, and that the percentage of closed flux tends to increase with increasing cloud size. The results are similar to those found at 1 AU, implying that the rate at which a cloud opens, presumably by interchange reconnection back at the Sun, slows significantly as its leading edge moves further out into the heliosphere.