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Dynamic Structures in Plasma Turbulence

#1851


Dynamic Structures in Plasma Turbulence: Measurement of Characteristics and Determination of General Features

Tech Area / Field

  • PHY-PLS/Plasma Physics/Physics

Status
3 Approved without Funding

Registration date
19.04.2000

Leading Institute
Institute of General Physics named after A.M. Prokhorov RAS, Russia, Moscow

Supporting institutes

  • VNIIEF, Russia, N. Novgorod reg., Sarov

Collaborators

  • URA 0073/Universite Paris-Sud, France, Orsay\nNational Institute for Fusion Science, Japan, Gifu-ken\nEURATOM-Ciemat, Spain, Madrid\nOak Ridge National Laboratory, USA, TN, Oak Ridge

Project summary

The aim of the Project is to determine general features of dynamic structures in various kinds of plasma turbulence, such as vortices, solitons in ion-acoustic or drift turbulence etc. An investigation of plasma turbulence is one of fundamental scientific problems existing now in plasma physics. At present, studies of a dynamic structure of plasma turbulence attract particular attention. These studies are related both to a fundamental problem, namely of creating a model of structural plasma turbulence, and to an applied problem in connection with attempts to explain anomalous transport in the edge plasma in toroidal magnetic confinement systems – devices involved in the fusion quest and considered as candidates for a fusion reactor.
In the last few years, studies of low-frequency turbulence have been carried out at the General Physics Institute. In the first experiments in a linear model device, it has been shown that structures exist in ion-acoustic turbulence of a magnetized current-carrying plasma. Further, these structures were identified as ion-acoustic solitons, and their existence was demonstrated in an afterglow plasma. Experiments on studying turbulence in the edge plasma in the L-2 stellarator also confirmed that low-frequency plasma turbulence appears in the form of structures, specifically, stable poloidal extended structures tens of centimeters in length. In deeper layers in the plasma, in the region of drift instability, vortex structures were observed.
At the General Physics Institute, much experience is gained both on measuring the characteristics of plasma turbulence and on data processing by the wavelet-analysis and probability analysis.
Plasma-discharge devices of various types have been created and are now in operation in the All-Russia Research Institute of Experimental Physics. The created diagnostic complex for optical and probe diagnostics permits processing of long arrays of information. Much experience gained in the plasma studies permits experiments on plasma turbulence to be successfully carried out at the Institute.
In the course of project implementation, it is suggested to solve the following problems:
-to adapt the currently available methods of spectral and probability analysis for studying the structural properties of low-frequency and high-frequency anisotropic turbulence in plasma;
-to carry out measurements and analysis of structures of strong low-frequency plasma turbulence;
-to carry out measurements and analysis of structures of strong high-frequency Langmuir turbulence;
-to carry out measurements and study of a nonlinear mixing of structures when high-frequency and low-frequency instabilities are both present in the plasma;
-to analyze the influence of coherent structures on transport and mixing;
-to distinguish the common features of the turbulent processes under study.


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