TJ-II:Turbulence: Difference between revisions

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Improving our understanding of turbulence is hard, due to (1) the complexity of fusion-grade plasmas (the presence of charged particles and magnetic fields make this into a much harder topic than fluid turbulence), (2) the enormous variety of plasma instabilities, and (3) the difficulty of diagnosing the plasma due to the hostile conditions inside the plasma.
Improving our understanding of turbulence is hard, due to (1) the complexity of fusion-grade plasmas (the presence of charged particles and magnetic fields make this into a much harder topic than fluid turbulence), (2) the enormous variety of plasma instabilities, and (3) the difficulty of diagnosing the plasma due to the hostile conditions inside the plasma.


Our work on turbulence has focussed mainly on the analysis of edge [[TJ-II:Langmuir Probes|Langmuir probe]] data, although some analysis was done on other types of data (e.g., [[TJ-II:Reflectometry|reflectometry]] signals). Much effort was devoted to the development of new analysis techniques.
Our work on turbulence has focussed mainly on the analysis of edge [[TJ-II:Langmuir Probes|Langmuir probe]] data, although some analysis was done on other types of data (e.g., [[TJ-II:Reflectometry|reflectometry]] signals). Much effort was devoted to the development of new [[data analysis techniques]].


=== Bicoherence and wavelets ===
=== Bicoherence and wavelets ===
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See also: [[TJ-II:Fast camera]].
See also: [[TJ-II:Fast camera]].


== See also ==
=== Causality detection ===


* [[Causality detection]]
To disentangle the complex relation between fluctuating variables, a technique for [[Causality detection]] has been used.
<ref>B.Ph. van Milligen, G. Birkenmeier, M. Ramisch, T. Estrada, C. Hidalgo, and A. Alonso, Causality detection and turbulence in fusion plasmas, [[doi:10.1088/0029-5515/54/2/023011|Nucl. Fusion '''54''' (2014), 023011]]</ref>
It has revealed that magnetic fluctuations may play an important role in the [[H-mode|L-H transition]].
<ref>B.Ph. van Milligen, T. Estrada, B.A. Carreras, E. Ascasíbar, C. Hidalgo, I. Pastor, J.M. Fontdecaba, R. Balbín, and the TJ-II Team, The causal impact of magnetic fluctuations in slow and fast L–H transitions at TJ-II, [[doi:10.1063/1.4958807|Phys. Plasmas '''23''' (2016) 072305]]</ref>


== References ==
== References ==
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