Turbulence at kinetic scales is an unresolved and ubiquitous phenomenon that characterizes both space and laboratory plasmas. Recently, new theories, in situ spacecraft observations and numerical simulations suggest a novel scenario for turbulence, characterized by a so-called phase-space cascade - the formation of fine structures, both in physical and velocity-space. This new concept is here extended by directly taking into account the role of inter-particle collisions, modeled through the nonlinear Landau operator or the simplified Dougherty operator. The characteristic times, associated with inter-particle correlations, are derived in the above cases. The implications of introducing collisions on the phase-space cascade are finally discussed.

Collisions, Kinetic plasmas, Plasma turbulence, Space plasmas
dx.doi.org/10.1088/1361-6587/ab04d5
Plasma Physics and Controlled Fusion
Centrum Wiskunde & Informatica, Amsterdam, The Netherlands

Pezzi, O, Valentini, F, Servidio, S, Camporeale, E, & Veltri, P. (P.). (2019). Fourier-Hermite decomposition of the collisional Vlasov-Maxwell system: Implications for the velocity-space cascade. Plasma Physics and Controlled Fusion, 61(5). doi:10.1088/1361-6587/ab04d5