Enhanced velocity diffusion in slow-growing 1-D langmuir turbulence
Numerical simulations show an enhancement of the 1-D velocity diffusion coefficient over the quasilinear value in the regime where the autocorrelation time is much smaller than the linear growth time or resonance broadening time. The diffusion enhancement occurs when the resonance broadening time is small compared with the linear growth time. These simulations are self consistent, use a hybrid PIC/spectral symplectic integration method, and have enough modes to be in the continuous spectrum limit. That is, even at the initial amplitudes the intermode spacing is sufficiently small that the resonance overlap parameter is large. A possible mechanism for the enhanced diffusion (spontaneous spectrum discretization) is discussed.
KeywordsSpontaneous Emission Mode Coupling Vlasov Equation Linear Growth Rate Autocorrelation Time
Unable to display preview. Download preview PDF.
- A. A. Vedenov, E. P. Velikhov, and R. Z. Sagdeev, Nucl. Fusion Suppl. 2, 465 (1962).Google Scholar
- Nicholson, D.R., Introduction to Plasma Theory, (John Wiley & Sons, New York, 1983).Google Scholar
- Liang, Y. M., and P. H. Diamond, Comments Plasma Phys. Controlled Fusion 15, 139 (1993).Google Scholar
- Escande, D.F., in Hamiltonian dynamical systems, R.S. MacKay and J.D. Meiss ed. (Adam Hilger, Bristol, 1987).Google Scholar
- Zekri, Stephane, Approche Hamiltonienne de la turbulence faible de Langmuir, Doctoral dissertation, Université de Provence, Marseille-Aix II (1993).Google Scholar
- N. A. Krall and A. W. Trivelpiece, Principles of Plasma Physics, (San Francisco Press, Inc. San Francisco, 1986).Google Scholar
- S. Ichimaru, Basic Principles of Plasma Physics, A Statistical Approach, (W. A. Benjamin, Reading, MA, 1973).Google Scholar
- Guyomarc'h, D., F. Doveil, and A. Guarino, Bull. Am. Phys. Soc. 41, 1458 (1996).Google Scholar