Multi-scale gyrokinetic simulation of tokamak plasmas: enhanced heat loss due to cross-scale coupling of plasma turbulence. (17th December 2015)

• Record Type: Journal Article
• Authors: Howard, N.T.; Holland, C.; White, A.E.; Greenwald, M.; Candy, J.
• Is Part Of: Nuclear fusion. Volume 56:Number 1(2016:Jan.)
• Publication Date: 2015-12-17
• Subjects: gyrokinetics -- plasma turbulence -- validation -- multi-scale -- multiscale; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/56/1/014004
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: The transport of heat in laboratory and astrophysical plasmas is dominated by the complex nonlinear dynamics of plasma turbulence. In magnetically confined plasmas used for fusion energy research, turbulence is responsible for cross-field transport that limits the performance of tokamak reactors. We report a set of novel gyrokinetic simulations that capture ion and electron-scale turbulence simultaneously, revealing the dynamics of cross-scale energy transfer and zonal flow modification that give rise to heat losses. Multi-scale simulations are required to match experimental ion and electron heat fluxes and electron profile stiffness, establishing the applicability of the newly discovered physics to experiment. Importantly, these results provide a likely explanation for the loss of electron heat from tokamak plasmas, the 'great unsolved problem' (Bachelor et al (2007 Plasma Sci. Technol .9 312–87)) in plasma turbulence and the projected dominant loss channel in ITER.