Development of initial perturbation in plasma systems subject to flow instabilities. New types of dissipative flow instabilities

• Published in: The European physical journal. D, Atomic, molecular, and optical physics Vol. 79; no. 7
• Main Author: Rostomyan, Eduard V.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 21.07.2025; Springer Nature B.V
• Subjects: Applications of Nonlinear Dynamics and Chaos Theory; Atomic; Constraining; Cyclotrons; Dissipation; Electron beams; Electrons; Geometry; Magnetohydrodynamic stability; Molecular; Motion stability; Optical and Plasma Physics; Perturbation; Physical Chemistry; Physics; Physics and Astronomy; Plasma; Quantum Information Technology; Quantum Physics; Regular Article - Plasma Physics; Spectroscopy/Spectrometry; Spintronics; Waveguides
• ISSN: 1434-6060; 1434-6079
• DOI: 10.1140/epjd/s10053-025-01018-6

The solutions to the classical problem of initial perturbation development (PIPD) for various types of flow instabilities (FI) in dissipative plasma are presented as well as the consequences. FI are due to the relative motion of plasma components (beam-plasma instabilities (BPI), the Buneman instability, etc.). The problem provides the most complete information on developing instabilities. The usual stumbling block in such type problems—the integral for the developing fields with the dispersion relation in the denominator of the integrand—for the first is overcome by direct integration. The holistic and versatile pictures of various FI spatiotemporal evolutions are presented. They show that with an increase in the level of dissipation any FI transforms into dissipative flow instability (DFI). Until recently, only one type of DFI in beam-plasma systems was known. Its maximal growth rate is ∼ n b / ν ( n b is the beam density, ν is the plasma collision frequency). All BPI regardless on type (Cherenkov, cyclotron, etc.) transform into it. Two new, previously unknown types of DFI follow from PIPD solutions. The first one develops in systems where the e-beam and the plasma are spatially separated by a significant distance. Its growth rate is ∼ n b / ν . The second new DFI develops in a uniform cross-section magnetized plasma-filled waveguide with an over-limiting e-beam. Its maximal growth rate is ∼ n b / ν . Both new dissipative instabilities in beam-plasma systems (DIBPSs) develop in geometry similar to geometry of plasma microwave devices based on relativistic e-beams. The geometry is cylindrical waveguide with thin tubular plasma and thin tubular e-beam of grater radius. The study on these devices has two basic trends of development: increasing power and operating frequency. To increase the power it is necessary to increase beam current up to over-limiting values. Increasing frequency leads to decreasing of the skin-depth in the walls of resonators. Dissipation increases and the conditions for the new DIBPS development may be satisfied. This emphasizes importance of investigations on new DIBPS. Graphical abstract