Scrape-off layer turbulence in TCV: evidence in support of stochastic modelling

0459853 - ÚFP 2017 RIV GB eng J - Článek v odborném periodiku
Theodorsen, A. - Garcia, O.E. - Horáček, Jan - Kube, R. - Pitts, R.A.
Scrape-off layer turbulence in TCV: evidence in support of stochastic modelling.
Plasma Physics and Controlled Fusion. Roč. 58, č. 4 (2016), č. článku 044006. ISSN 0741-3335. E-ISSN 1361-6587
Grant CEP: GA ČR(CZ) GAP205/12/2327
Institucionální podpora: RVO:61389021
Klíčová slova: turbulence * intermittency * transport * scrape-off layer * tcv * plasma * tokamak
Obor OECD: Fluids and plasma physics (including surface physics)
Impakt faktor: 2.392, rok: 2016
http://iopscience.iop.org/article/10.1088/0741-3335/58/4/044006/meta

Intermittent fluctuations in the TCV scrape-off layer have been investigated by analysing
long Langmuir probe data time series under stationary conditions, allowing calculation of
fluctuation statistics with high accuracy. The ion saturation current signal is dominated by the
frequent occurrence of large-amplitude bursts attributed to filament structures moving through
the scrape-off layer. The average burst shape is well described by a double-exponential
wave-form with constant duration, while the waiting times and peak amplitudes of the bursts
both have an exponential distribution. Associated with bursts in the ion saturation current
is a dipole-shaped floating potential structure and radially outwards directed electric drift
velocity and particle flux, with average peak values increasing with the saturation current burst
amplitude. The floating potential fluctuations have a normal probability density function while
the distributions for the ion saturation current and estimated radial velocity have exponential
tails for large fluctuations. These findings are discussed in the light of prevailing theories for
filament motion and a stochastic model for intermittent scrape-off layer plasma fluctuations.
Trvalý link: http://hdl.handle.net/11104/0260011