2024/01/10 by J. M. Losada, Losada, J. M., O. Paikina +3
Physics and Astronomy · #FOS: Physical sciences #Ionosphere and magnetosphere dynamics #Magnetic confinement fusion research #Plasma Physics (physics.plasm-ph) #Solar and Space Plasma Dynamics
paper · pdf · doi:10.48550/arxiv.2401.05198
openalex publication_date 2024/01/10 · openalex created_date 2024/01/13 · openalex updated_date 2026/07/28
A stochastic model for a superposition of uncorrelated pulses with a random distribution of amplitudes, sizes, and velocities is analyzed. The pulses are assumed to move radially with fixed shape and amplitudes decreasing exponentially in time due to linear damping. The pulse velocities are taken to be time-independent but randomly distributed. The implications of a broad distribution of pulse amplitudes and velocities, as well as correlations between these, are investigated. Fast and large-amplitude pulses lead to broad and flat average radial profiles with order unity relative fluctuations in the scrape-off layer. For theoretically predicted blob velocity scaling relations, the stochastic model reveals average radial profiles similar to the case of a degenerate distribution of pulse velocities but with more intermittent fluctuations. The average profile e-folding length is given by the product of the average pulse velocity and the linear damping time due to losses along magnetic field lines. The model describes numerous common features from experimental measurements and underlines the role of large-amplitude fluctuations for plasma-wall interactions in magnetically confined fusion plasmas.