Combining variations of filaments/plasma with and junctions and layers Professor Williams interprets beads along the (Birkeland?) filaments, plasma currents and more to be parts of the interstellar filament and hub system. The images come from the video (links to 2MB gif).
Swirling motions in clouds of cold, dense gas have given, for the first time, an active insight into how gravity creates the compact cores from which stars form in the interstellar medium.
... "We've known for some time that dusty, filamentary cloud structures are ubiquitous in the Milky Way's interstellar medium. We also know that the densest of these filaments fragment into compact pockets of cold gas that then collapse under their own gravity to form individual stars. However, there's still been a question mark over how, exactly, this happens."
SDC13 is a remarkable cloud network of four filaments converging on a central hub, with a total mass of gas equivalent to a thousand of our Suns ... using the Jansky Very Large Array (JVLA) and the Green Bank Telescope (GBT), have now captured the effects of gravity on ammonia gas moving within the SDC13 system.
Material is pulled from surrounding filaments and accreted onto cores dotted along the cloud structure, converting gravitational potential energy into kinetic energy in the process. Intense surges in the gas motion are observed at two-thirds of the cores that have yet to form stars.
Williams notes: "We believe that the same processes are at work at the filament junction, where both the largest internal motions of the gas and the most massive cores are found. We also speculate that strong acceleration gradients are generated at the hub centre resulting in large accumulation of matter and the formation of massive cores. Hence, our results reveal that this type of interstellar filament and hub system represents a privileged location for the formation of the most massive of stars in the Galaxy."
From a related SDC13 infrared dark clouds: Longitudinally collapsing filaments? paper in 2014.
Formation of stars is now believed to be tightly linked to the dynamical evolution of interstellar filaments in which they form. In this paper we analyze the density structure and kinematics of a small network of infrared dark filaments, SDC13, observed in both dust continuum and molecular line emission with the IRAM 30 m telescope. These observations reveal the presence of 18 compact sources amongst which the two most massive, MM1 and MM2, are located at the intersection point of the parsec-long filaments. The dense gas velocity and velocity dispersion observed along these filaments show smooth, strongly correlated, gradients.