Two-stream instability with a growth rate insensitive to collisions in a dissipative plasma jet
The two-stream instability (Buneman instability) is traditionally derived as a collisionless instability with the presumption that collisions inhibit this instability. We show here via a combination of a collisional two-fluid model and associated experimental observations made in the Caltech plasma jet experiment, that in fact, a low-frequency mode of the two-stream instability is indifferent to collisions. Despite the collision frequency greatly exceeding the growth rate of the instability, the instability can still cause an exponential growth of electron velocity and a rapid depletion of particle density. Nevertheless, high collisionality has an important effect as it enables the development of a double layer when the cross section of the plasma jet is constricted by a kink-instigated Rayleigh–Taylor instability.
© 2023 Author(s). Published under an exclusive license by AIP Publishing. This study was supported by NSF Award No. 2105492 and by AFOSR Award No. FA9550–21-1–0379. Author Contributions. Yi Zhou: Formal analysis (equal); Investigation (equal); Methodology (equal); Software (equal); Validation (equal); Visualization (equal); Writing – original draft (equal); Writing – review & editing (equal). Paul M. Bellan: Conceptualization (equal); Formal analysis (equal); Funding acquisition (equal); Investigation (equal); Methodology (equal); Project administration (equal); Supervision (equal); Validation (equal); Writing – original draft (equal); Writing – review & editing (equal). DATA AVAILABILITY. The data that support the findings of this study are available from the corresponding author upon reasonable request. The authors have no conflicts to disclose.