A statistical study of gyro-averaging effects in a reduced model of drift-wave transport

Author(s)

da Fonseca, J. D. ; del-Castillo-Negrete, D. ; Sokolov, I. M. ; Caldas, I. L.

• Document type: Journal article
• Source: Physics of Plasmas; v. 23, n. 8 AUG 2016.
• Web of Science Citations: 1

Abstract

A statistical study of finite Larmor radius (FLR) effects on transport driven by electrostatic drift-waves is presented. The study is based on a reduced discrete Hamiltonian dynamical system known as the gyro-averaged standard map (GSM). In this system, FLR effects are incorporated through the gyro-averaging of a simplified weak-turbulence model of electrostatic fluctuations. Formally, the GSM is a modified version of the standard map in which the perturbation amplitude, K-0, becomes K(0)J(0)((rho) over cap), where J(0) is the zeroth-order Bessel function and (rho) over cap is the Larmor radius. Assuming a Maxwellian probability density function (pdf) for (rho) over cap, we compute analytically and numerically the pdf and the cumulative distribution function of the effective drift-wave perturbation amplitude K(0)J(0)((rho) over cap). Using these results, we compute the probability of loss of confinement (i.e., global chaos), P-c, and the probability of trapping in the main drift-wave resonance, P-t. It is shown that P-c provides an upper bound for the escape rate, and that P-t provides a good estimate of the particle trapping rate. The analytical results are compared with direct numerical Monte-Carlo simulations of particle transport. Published by AIP Publishing. (AU)

• FAPESP's process: 12/10240-6 - Particle Transport in Magnetically Confined Plasmas
• Grantee: Julio César David da Fonseca
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 11/19296-1 - Nonlinear dynamics
• Grantee: Iberê Luiz Caldas
• Support Opportunities: Research Projects - Thematic Grants