Review of plasma turbulence experiments

Abstract

Understandings of turbulent plasma have been developed along with nuclear fusion research for more than a half century. Long international research has produced discoveries concerning turbulent plasma that allow us to notice the hidden nature and physics questions that could contribute to other scientific fields and the development of technologies. Guiding concepts have been established up to now that stimulate investigations on turbulent plasma. Research based on concepts concerning symmetry breaking and global linkage requires observing the entire field of plasma turbulence for an ultimate understanding of plasma. This article reviews the achievements as well as contemporary problems regarding turbulence experiments associated with strongly magnetized plasmas in the last and present century, and introduces forthcoming experimental issues, including new diagnostics and physics-oriented devices related to plasma turbulence.

Fascinating physics at the edge of magnetic fusion devices

“…'snowflake' and 'Super-X' divertors, magnetic configuration with 'negative triangularity'); implementation of liquid metals (e.g. Li) as the material accommodating the heat flux and, potentially, promising a new (zero-recycling) regime of a tokamak operation, the indications of which were observed in experiments; the peculiarities of edge plasma physics in stellarators, etc (see [60][61][62][63][64][65][66][67][68][69][70][71][72][73] and the reference therein, where these topics are discussed in some detail).…”

Importance of accurate consideration of the electron inertia in hybrid-kinetic simulations of collisionless plasma turbulence: 1. The 2D limit

“…The nature of collisionless plasma turbulence, from large (fluid) down to small (kinetic) scales, is a key unsolved problem in plasma physics 1 . It finds its importance in many physical situations ranging from hot laboratory to astrophysical plasmas 2,3 . In these predominantly collisionless plasmas, turbulence develops from fluid to kinetic scales where its energy is finally dissipated into heat.…”

Fluid energy cascade rate and kinetic damping: new insight from 3D Landau-fluid simulations

“…Yet, enhancing our understanding of turbulent plasmas would provide the keys to solve a variety of problems related to energy dissipation, particle heating and acceleration. Examples of systems where these processes are crucial include the solar wind (SW) and planetary magnetospheres (Bruno & Carbone 2005;Matthaeus & Velli 2011;Goldstein et al 1995;Sahraoui et al 2020), accretion flows around compact objects (Balbus & Hawley 1998;Quataert & Gruzinov 1999) and fusion devices (Diamond et al 2005;Garbet 2006;Fujisawa 2021). In the SW, the heating problem is reflected by the slow decline of ion temrenaud.ferrand@lpp.polytechnique.fr perature (as function of the radial distance from the sun) in comparison with the prediction from the adiabatic expansion model of the wind (Richardson et al 1995).…”