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

Here, a statistical study of finite Larmor radius (FLR) effects on transport driven by electrostatic driftwaves 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, K0, becomes K0J0($$\hat{p}$$), where J0 is the zeroth-order Bessel function and $$\hat{p}$$ s the Larmor radius. Assuming a Maxwellian probability density function (pdf) for $$\hat{p}$$ , we compute analytically and numerically the pdf and the cumulative distribution function of the effective drift-wave perturba- tion amplitude K0J0($$\hat{p}$$). Using these results, we compute the probability of loss of confinement (i.e., global chaos), Pc provides an upper bound for the escape rate, and that Pt rovides a good estimate of the particle trapping rate. Lastly. the analytical results are compared with direct numerical Monte-Carlo simulations of particle transport.
Authors:
 [1] ;  [2] ;  [3] ;  [1]
  1. Univ. of Sao Paulo (Brazil)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Humboldt Univ. of Berlin (Germany). Physics Inst.
Publication Date:
OSTI Identifier:
1333071
Grant/Contract Number:
AC05-00OR22725;2011/19296-1; 203460/ 2014-6; 2012/10240-6;
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 8; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING Chaos; electrostatics