Intermittency in the Magnetic Hump in the VLISM

Abstract

Voyager 1 has been moving through the very local interstellar medium (VLISM) for ~1 solar cycle, from 122.58 au on 2012/DOY 238 (August 25) to 158.5 au on 2023.0. A magnetic hump was observed, beginning with an abrupt increase (jump) in the magnetic field strength B and proton density N by a factor of 1.35 and 1.36, respectively, in the course of ~8 days, ending at ~2020/DOY 147, after which it remained above the pre-jump levels for 2.6 yr, and it is still increasing. Unlike the three previous jumps, which were followed by a slow decrease in B, B in the magnetic hump continued to increase to a maximum value ~0.56 nT at ~2021/DOY 146.7. This paper discusses the intermittency of the magnetic field components and strength in the magnetic hump, and compares them with previous values in the VLISM. We consider the intermittency of the increments of B and its components observed on a scale of one day. The distribution function (the Tsallis distribution or q-distribution function) of the increments of hourly averages of the components of B had a Gaussian core associated with randomness in the observations, and it had two symmetric tails associated with the observed intermittency. The parameters q-dBR1, q-dBT1, and q-dBN1 increased slightly to a broad maximum with q = ~1.4 between 2018 and 2019, and then decreased to q ~ 1 (corresponding to no intermittency) in 2022. The Z-component of the magnetic field is within 4 ± 4 counts (0.02 nT ± 0.02 nT).