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Author Garcia, O. E. ♦ Kube, R. ♦ Theodorsen, A. ♦ Pécseli, H. L.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PLASMA PHYSICS AND FUSION TECHNOLOGY ♦ AMPLITUDES ♦ CORRELATION FUNCTIONS ♦ CORRELATIONS ♦ DISTRIBUTION ♦ ERRORS ♦ FLUCTUATIONS ♦ FORECASTING ♦ PLASMA DENSITY ♦ PLASMA SCRAPE-OFF LAYER ♦ PLASMA SIMULATION ♦ PROBABILITY ♦ PROBABILITY DENSITY FUNCTIONS ♦ PULSE SHAPERS ♦ PULSES ♦ STOCHASTIC PROCESSES ♦ TRANSPORT THEORY ♦ WALL EFFECTS ♦ WALLS
Abstract A stochastic model is presented for intermittent fluctuations in the scrape-off layer of magnetically confined plasmas. The fluctuations in the plasma density are modeled by a super-position of uncorrelated pulses with fixed shape and duration, describing radial motion of blob-like structures. In the case of an exponential pulse shape and exponentially distributed pulse amplitudes, predictions are given for the lowest order moments, probability density function, auto-correlation function, level crossings, and average times for periods spent above and below a given threshold level. Also, the mean squared errors on estimators of sample mean and variance for realizations of the process by finite time series are obtained. These results are discussed in the context of single-point measurements of fluctuations in the scrape-off layer, broad density profiles, and implications for plasma–wall interactions due to the transient transport events in fusion grade plasmas. The results may also have wide applications for modelling fluctuations in other magnetized plasmas such as basic laboratory experiments and ionospheric irregularities.
ISSN 1070664X
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-05-15
Publisher Place United States
Journal Physics of Plasmas
Volume Number 23
Issue Number 5


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