tokens: by larger quiet regions in which B varied relatively slowly, and contained small amplitude waves and turbulence. Thus, the basic structure of the VLISM observed between 2012/DOY 238 and 2020/DOY 182 consists of four jump–ramp structures associated with the four maxima in B between 2012 and 2020, separated by four quiet intervals. The timescales of the jumps that moved past V1 were ∼5.4 days and 3.3 days for the shocks sh1 and sh2 observed on ∼2012.9746 (DOY 335) and 2014.6 (DOY 236), respectively. The corresponding timescales for the jumps associated with pressure fronts were ∼35 days and ∼8 days for the pressure fronts pf1 and pf2 observed on ∼2016/346 and ∼2020/147, respectively. The corresponding timescale for the ramp associated with sh1 was ∼162 days, during which time B decreased exponentially from ∼2012.9746/335 to ∼2013.35759/131. The timescale of the ramp associated with sh2 was 276 days, when B decreased linearly (with notable fluctuations related to fine-scale features) from 2014.68212 to 2015.37669. In the ramp following the pressure front pf1, B declined nearly monotonically until 2018.41885, during an interval of 402 days. We do not yet have V1 observations during the ramp associated with pf2. We have shown that jump–ramp features of B in the VLISM and the larger quiet intervals between them are the fundamental features of the VLISM. These features were actually specially configured waves that were generated by the interaction of heliosheath with the heliopause and then propagated through the VLISM, presumably interacting with one another to produce the results observed by Voyager 1. Smaller scale waves and turbulence exist within these features. Mathematical techniques such as Hilbert transforms and wavelet transforms (Zhao et al. 2020 ) and Fourier methods (Fraternale et al. 2019 ) are very valuable tools for studying the VLISM over a wide range of scales. However, it is also essential to understand the basic structure and dynamics of the large-scale flows on scales of hours to a decade presented in this paper. This can best be done by improving the MHD models and the corresponding input observations. A number of models have been discussed in the literature, including those by Fermo et al. ( 2015 ), Zirnstein et al. ( 2018 ), and Kim et al. ( 2017 ). However, none of these models reproduce the kind of pattern of shocks, pressure pulses, and quiet regions shown in Figure 2 . Appendix New Method for Deriving Plasma Densities The Voyager PWS instrument (Scarf Gurnett 1977 ) includes a wideband waveform receiver that captures digitized waveforms in the range of 50 Hz to above 10 kHz. Waveform captures include 1600 4 bit samples obtained at a rate of 28,800 samples per second. On board, 800 of these waveform captures are obtained at a rate of one every 60 ms covering 48 seconds (one frame). Due to decreasing telemetry performance at the large distances of Voyager, beginning in 1992 November, only one of every five waveform
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