Stochastic modelling of blob-like plasma filaments in the scrape-off layer: Theoretical foundation
arXiv:2210.09676 · doi:10.1063/5.0144885
Abstract
A stochastic model is presented for a super-position of uncorrelated pulses with a random distribution of amplitudes, sizes, velocities and arrival times. The pulses are assumed to move radially with fixed shape and amplitudes decaying exponentially in time due to linear damping. The pulse velocities are taken to be time-independent but randomly distributed. The implications of a distribution of and correlations between pulse sizes, velocities and amplitudes are investigated. Expressions for the lowest order statistical moments, probability density functions and correlation functions for the process are derived for the case of exponential pulses and a discrete uniform distribution of pulse velocities. The results describe many features of high average particle densities, broad and flat average radial profiles, and large-amplitude, intermittent fluctuations at the boundary region of magnetically confined plasmas. The stochastic model elucidates how these phenomena are related to the statistics of blob-like structures.
References in corpus (6)
- An experimental investigation on the high density transition of the Scrape-off Layer transport in ASDEX Upgrade
- 3D Simulations of Plasma Filaments in the Scrape Off Layer: A Comparison with Models of Reduced Dimensionality
- Recent progress towards a quantitative description of filamentary SOL transport
- Convergence of statistical moments of particle density time series in scrape-off layer plasmas
- Interpretation of scrape-off layer profile evolution and first-wall ion flux statistics on JET using a stochastic framework based on filamentary motion
- Characterization of edge and scrape-off layer fluctuations using the fast Li-BES system on COMPASS