Effect of electron-cyclotron resonance heating conditions on the local parameters of short-wavelength plasma turbulence in the L-2M stellarator

Batanov, G. M.; Borzosekov, V. D.; Колик, Л. В.; Malakhov, D. V.; Petrov, A. E.; Pshenichnikov, A. F.; Sarksyan, K. A.; Скворцова, Н. Н.; Kharchev, N. K.

doi:10.1134/s1063780x14040011

Cited by 2 publications

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“…Transition processes of two types are routinely observed in the L-2M plasma: the first type is caused by an abrupt change in the ECRH power, while the second happens spontaneously during heating at a constant power [21][22][23]. In the present study, we statistically analyze only transition processes caused by an abrupt increase in the ECRH power.…”

Section: Experimental Set-up and Data Analysis Techniquementioning

confidence: 99%

“…In the past two decades, a lot of fundamental problems were addressed. Let us mention some of them: deviation of the probability density function (PDF) of turbulent fluctuations from a normal distribution (see review [1]), a decrease in the turbulence level after the transition into the high-confinement mode (H-mode) [2][3][4][5][6], an increase in the level of short-wavelength density fluctuations ( r > is the fluctuations wavenumber, Т е is the electron temperature, М is the ion mass, and W i is the ion gyrofrequency) with increasing power of electron cyclotron resonance heating (ECRH), and correlation between the turbulence level and the growth rates of the electron temperature gradient mode and trapped electron mode [7][8][9][10][11][12]. Various statistical models of plasma turbulence have been created.…”

Section: Introductionmentioning

confidence: 99%

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Evolution of statistical properties of microturbulence during transient process under electron cyclotron resonance heating of the L-2M stellarator plasma

Batanov

Borzosekov

Gorshenin

et al. 2019

Plasma Phys. Control. Fusion

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The formalism of compound Cox processes was used for statistical analysis of turbulent density fluctuations of plasma during a transient process at electron cyclotron resonance heating of L-2M stellarator plasmas. Short-wavelength (k=20-30 cm −1 ) density fluctuations in the central region of the plasma column were measured by the collective backscattering technique. The transient process was caused by sputtering of wall coating and subsequent pulsed impurity injection into the plasma after a step-like increase of the heating power. The evolution of the following parameters was studied: probability density function (PDF) and dynamic and diffusive components of variance of density fluctuations increments. It was found that density fluctuations increments increase simultaneously with average electron density increase and electron temperature decrease during the transient process. It was shown that the PDF of fluctuation increments is characterized by the existence of heavy tails and it can be represented as a composition of four normal laws. Deviation from normal law that happens in the form of random bursts was observed. Duration and frequency of the bursts increases with the level of fluctuation increments and this increase is accompanied by the increase of both components of the variance.

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Section: Experimental Set-up and Data Analysis Techniquementioning

confidence: 99%