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Global gradient driven GENE gyrokinetic simulations are used to investigate TCV plasmas with negative triangularity. Considering a limited L-mode plasma, corresponding to an experimental triangularity scan, numerical results are able to reproduce the actual transport level over a major fraction of the plasma minor radius for a plasma with $delta_{rm LCFS}=-0.3$ and its equivalent with standard positive triangularity $delta$. For the same heat flux, a larger electron temperature gradient is sustained by $delta<0$, in turn resulting in an improved electron energy confinement. Consistently with the experiments, a reduction of the electron density fluctuations is also seen. Local flux-tube simulations are used to gauge the magnitude of nonlocal effects. Surprisingly, very little differences are found between local and global approaches for $delta>0$, while local results yield a strong overestimation of the heat fluxes when $delta<0$. Despite the high sensitivity of the turbulence level with respect to the input parameters, global effects appear to play a crucial role in the negative triangularity plasma and must be retained to reconcile simulations and experiments. Finally, a general stabilizing effect of negative triangularity, reducing fluxes and fluctuations by a factor dependent on the actual profiles, is recovered.
A long standing puzzle in fusion research comes from experiments where a sudden peripheral electron temperature perturbation is accompanied by an almost simultaneous opposite change in central temperature, in a way incompatible with local transport m
Coulomb implosion mechanism of the negatively charged ion acceleration in laser plasmas is proposed. When a cluster target is irradiated by an intense laser pulse and the Coulomb explosion of positively charged ions occurs, the negative ions are acce
The negative power absorption in low pressure plasmas is investigated by means of an analyical model which couples Boltzmanns equation and the quasi-stationary Maxwells equation. Exploiting standard Hilbert space methods an explicit solution for both
The aim of this work is to provide an understanding of detachment at TCV with emphasis on analysis of the Balmer line emission. A new Divertor Spectroscopy System has been developed for this purpose. Further development of Balmer line analysis techni
We report on experimental evidence of visco-elastic effects in a strongly coupled dusty plasma through investigations of the propagation characteristics of low frequency dust acoustic waves and by excitations of transverse shear waves in a DC discharge Argon plasma.