Non-modal approach to linear theory: marginal stability and the dissipation of turbulent fluctuations

Abstract

The non-modal approach for a linearized system differs from a normal mode analysis by following the temporal evolution of some perturbed equilibria, and therefore includes transient effects. We employ a non-modal approach for studying the stability of a bi-Maxwellian magnetized plasma using the Landau fluid model, which we briefly describe. We show that bi-Maxwellian stable equilibria can support transient growth of some physical quantities, and we study how these transients behave when an equilibrium approaches its marginally stable condition. This is relevant to anisotropic plasma, that are often observed in the solar wind with a temperature anisotropy close to values that can trigger a kinetic instability. The results obtained with a non-modal approach are relevant to a re-examination of the concept of linear marginal stability. Moreover, we discuss the topic of the dissipation of turbulent fluctuations, suggesting that the non-modal approach should be included in future studies.

11 pages, 6 figures

References in corpus (7)

• Magnetic fluctuation power near proton temperature anisotropy instability thresholds in the solar wind
• Universality of solar wind turbulent spectrum from MHD to electron scales
• Kinetic Simulations of Magnetized Turbulence in Astrophysical Plasmas
• Multi-scale Hall-MHD turbulence in the solar wind
• Whistler Wave Cascade in Solar Wind Plasma
• Cascade and Damping of Alfvén-Cyclotron Fluctuations: Application to Solar Wind Turbulence Spectrum
• Transient growth in stable collisionless plasma

Cited by in corpus (8)

• Can the Solar Wind be Driven by Magnetic Reconnection in the Sun's Magnetic Carpet?
• The dissipation of solar wind turbulent fluctuations at electron scales
• Generalized universal instability: Transient linear amplification and subcritical turbulence
• Space-filter techniques for quasi-neutral hybrid-kinetic models
• Comparison of linear modes in kinetic plasma models
• A Linear Technique to Understand Non-Normal Turbulence Applied to a Magnetized Plasma
• The nonmodal kinetic theory for the electrostatic instabilities of a plasma with a sheared Hall current
• Non-modal Simon-Hoh instability of a plasma with a shearing Hall current