Weak Plasma Turbulence Theory and Some Other Items of Plasma Kinetics

1998 ◽  
Vol 51 (5) ◽  
pp. 843 ◽  
Author(s):  
V. I. Erofeev
Keyword(s):  
Plasma Turbulence ◽  
Collision Integral ◽  
Turbulence Theory ◽  
Traditional Theory ◽  
Nonlinear Structures ◽  
Kinetic Description ◽  
New Approach ◽  
Plasma Kinetics ◽  
Plasma Kinetic ◽  
Wave Collision

A new approach to a plasma kinetic description is discussed, the beginnings of which were published recently (Erofeev 1997a). It is shown that calculations of the three-wave collision integral following this approach confirm the intensity and structure of the three-wave collision integral obtained in the traditional theory. The reported kinetics extend the area of applicability for the weak plasma turbulence theory: apart from waves it properly accounts for the effect of various other plasma nonlinear structures of the type of solitons, drift vortices, collapsing cavities and so on. Some directions for further studies are also discussed.

Asymptotic propagators and trajectories in plasma turbulence theory

1979 ◽  
Vol 21 (9) ◽  
pp. 749-779 ◽  
Author(s):  
J H Misguich ◽  
R Balescu
Keyword(s):  
Plasma Turbulence ◽  
Turbulence Theory

scholarly journals Multidimensional Iterative Filtering: a new approach for investigating plasma turbulence in numerical simulations

2020 ◽  
Vol 86 (5) ◽  
Author(s):  
Emanuele Papini ◽  
Antonio Cicone ◽  
Mirko Piersanti ◽  
Luca Franci ◽  
Petr Hellinger ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Complex Dynamics ◽  
Spatial Scales ◽  
Plasma Turbulence ◽  
Astrophysical Plasmas ◽  
Plasma Dynamics ◽  
New Approach ◽  
Particle In Cell ◽  
Multidimensional Signals ◽  
Iterative Filtering

Turbulent space and astrophysical plasmas exhibit a complex dynamics, which involves nonlinear coupling across different temporal and spatial scales. There is growing evidence that impulsive events, such as magnetic reconnection instabilities, lead to a spatially localized enhancement of energy dissipation, thus speeding up the energy transfer at small scales. Capturing such a diverse dynamics is challenging. Here, we employ the Multidimensional Iterative Filtering (MIF) method, a novel technique for the analysis of non-stationary multidimensional signals. Unlike other traditional methods (e.g. based on Fourier or wavelet decomposition), MIF does not require any previous assumption on the functional form of the signal to be identified. Using MIF, we carry out a multiscale analysis of Hall-magnetohydrodynamic (HMHD) and hybrid particle-in-cell (HPIC) numerical simulations of decaying plasma turbulence. The results assess the ability of MIF to spatially identify and separate the different scales (the MHD inertial range, the sub-ion kinetic and the dissipation scales) of the plasma dynamics. Furthermore, MIF decomposition allows localized current structures to be detected and their contribution to the statistical and spectral properties of turbulence to be characterized. Overall, MIF arises as a very promising technique for the study of turbulent plasma environments.

Numerical Investigation of Mechanisms Underlying Oceanic Internal Gravity Wave Power-Law Spectra

2020 ◽  
Vol 50 (9) ◽  
pp. 2713-2733
Author(s):  
Yulin Pan ◽  
Brian K. Arbic ◽  
Arin D. Nelson ◽  
Dimitris Menemenlis ◽  
W. R. Peltier ◽  
...  
Keyword(s):  
Power Law ◽  
Gravity Waves ◽  
High Frequency ◽  
Internal Gravity Wave ◽  
Numerical Data ◽  
Field Measurements ◽  
Internal Gravity Waves ◽  
Collision Integral ◽  
Turbulence Theory ◽  
Nonlinear Interactions

AbstractWe consider the power-law spectra of internal gravity waves in a rotating and stratified ocean. Field measurements have shown considerable variability of spectral slopes compared to the high-wavenumber, high-frequency portion of the Garrett–Munk (GM) spectrum. Theoretical explanations have been developed through wave turbulence theory (WTT), where different power-law solutions of the kinetic equation can be found depending on the mechanisms underlying the nonlinear interactions. Mathematically, these are reflected by the convergence properties of the so-called collision integral (CL) at low- and high-frequency limits. In this work, we study the mechanisms in the formation of the power-law spectra of internal gravity waves, utilizing numerical data from the high-resolution modeling of internal waves (HRMIW) in a region northwest of Hawaii. The model captures the power-law spectra in broad ranges of space and time scales, with scalings ω−2.05±0.2 in frequency and m−2.58±0.4 in vertical wavenumber. The latter clearly deviates from the GM76 spectrum but is closer to a family of induced-diffusion-dominated solutions predicted by WTT. Our analysis of nonlinear interactions is performed directly on these model outputs, which is fundamentally different from previous work assuming a GM76 spectrum. By applying a bicoherence analysis and evaluations of modal energy transfer, we show that the CL is dominated by nonlocal interactions between modes in the power-law range and low-frequency inertial motions. We further identify induced diffusion and the near-resonances at its spectral vicinity as dominating the formation of power-law spectrum.

Computer-Based Thermodynamics

2002 ◽  
Vol 30 (4) ◽  
pp. 427-436
Author(s):  
Kenneth L. Tuttle ◽  
Chih Wu
Keyword(s):  
Parametric Analysis ◽  
Thermodynamic Cycle ◽  
Computer Assisted ◽  
Traditional Theory ◽  
Naval Academy ◽  
New Approach ◽  
Thermodynamic Cycles ◽  
Computer Based ◽  
Approach To Teaching ◽  
Assisted Instruction

A new computer-based approach to teaching thermodynamics is being developed and tried by two mechanical engineering professors at the U.S. Naval Academy. The course uses sophisticated software, in this case CyclePad, to work all of the homework problems. A new text, written with traditional theory but computer-based problems, accommodates the new approach. The new course is scheduled for Fall Term 2001 at the Naval Academy. Computer-based thermodynamics courses teach the same theory as traditional thermodynamics courses as well as the same types of problems. However, traditional thermodynamic cycle hand calculations are replaced by cycle calculations using CyclePad. This new example of Intelligent Computer-Assisted Instruction, ICAI, switches emphasis from learning cycle calculations to learning cause and effect through parametric analysis. Parametric analysis is made feasible through experimentation using computer models. For this, CyclePad has artificial intelligence, sensitivity analysis and graphical presentation capabilities. Traditionally, thermodynamics culminates in analysis of the thermodynamic cycles. In this course, students will progress well beyond traditional thermodynamics courses by emphasizing cycle analysis.

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