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.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1333071
- Alternate ID(s):
- OSTI ID: 1306688
- Journal Information:
- Physics of Plasmas, Vol. 23, Issue 8; ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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