The role of the plasma current in turbulence decrease during lower hybrid current drive

0509309 - ÚFP 2020 RIV US eng J - Článek v odborném periodiku
Antar, G. - Ekedahl, A. - Goniche, M. - Asghar, A. - Žáček, František
The role of the plasma current in turbulence decrease during lower hybrid current drive.
Physics of Plasmas. Roč. 24, č. 3 (2017), č. článku 032307. ISSN 1070-664X. E-ISSN 1089-7674
Institucionální podpora: RVO:61389021
Klíčová slova: scrape-off layer * transport * front
Obor OECD: Fluids and plasma physics (including surface physics)
Impakt faktor: 1.941, rok: 2017
Způsob publikování: Omezený přístup
https://aip.scitation.org/doi/10.1063/1.4978486

The interaction of radio frequency (RF) waves with edge turbulence has resurfaced after the results obtained on many tokamaks showing that edge turbulence decreases when the ion cyclotron frequency heating (ICRH) is switched on. Using the lower hybrid (LH) waves to drive current into tokamak plasmas, this issue presented contradicting results with some tokamaks (FTU & HT-7) showing a net decrease, similar to the ICRH results, and others (Tore Supra) did not. In this article, these apparent discrepancies among tokamaks and RF wave frequencies are removed. It is found that turbulence large-scale structures in the scrape-off layer decrease at high enough plasma currents (I-p) on the Tore Supra tokamak. We distinguish three regimes: At low I-p's, no modification is detected with statistical properties of turbulence similar to ohmic plasmas even with P-LH reaching 4.8MW. At moderate plasma currents, turbulence properties are modified only at a high LH power. At high plasma currents, turbulent large scales are reduced to values smaller than 1 cm, and this is accompanied by a net decrease in the level of turbulence of about 30% even with a moderate LH power.
Trvalý link: http://hdl.handle.net/11104/0300053