TJ-II: Physics of transport decoupling, an approach to measure the phase relation between density and temperature fluctuations: Difference between revisions

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Why is there decoupling between particle and energy transport channels at the transition to improved confinement regimes?. Physics behind uncoupled transport channels is a relevant open question for understanding both ELM control techniques (e.g. using RMP) as part of the ITER base-line scenario and the development of plasma scenarios without ELMs (e.g. I-mode). Interestingly, uncoupled transport channels has been also reported in stellarators (e.g. TJ-II <ref> C. Hidalgo et al., PPCF 46 (2004) 287A </ref>).  
Why is there decoupling between particle and energy transport channels at the transition to improved confinement regimes?. Physics behind uncoupled transport channels is a relevant open question for understanding both ELM control techniques (e.g. using RMP) as part of the ITER base-line scenario and the development of plasma scenarios without ELMs (e.g. I-mode). Interestingly, uncoupled transport channels has been also reported in stellarators (e.g. TJ-II <ref> C. Hidalgo et al., PPCF 46 (2004) 287A </ref>).  


Transport channel decoupling could be driven by any mechanism that leads to a modification of the cross-phase between density and temperature fluctuations caused by changing driving conditions [<ref> C. Hidalgo et al., Plasma Phys. Control. Fusion 59 (2017) 014051</ref>].   
Transport channel decoupling could be driven by any mechanism that leads to a modification of the cross-phase between density and temperature fluctuations caused by changing driving conditions [<ref> C. Hidalgo et al., PPCF 59 (2017) 014051</ref>].   


We propose to measure the phase relation between density and temperature fluctuations using a combined diagnostic based on a Retarting Field Analyzer (RFA) <ref> I. Nedzelskiy et al., RSI 82 (2011) 043505</ref> and Langmuir probes that has been recently developed in the TJ-II stellarator.
We propose to measure the phase relation between density and temperature fluctuations using a combined diagnostic based on a Retarting Field Analyzer (RFA) <ref> I. Nedzelskiy et al., RSI 82 (2011) 043505</ref> and Langmuir probes that has been recently developed in the TJ-II stellarator.
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