View source for TJ-II:Investigation of plasma asymmetries in the TJ-II stellarator and comparison with Gyrokinetic simulations

== Experimental campaign ==
2017 Spring

== Proposal title ==
'''Investigation of plasma asymmetries in the TJ-II stellarator and comparison with Gyrokinetic simulations'''

== Name and affiliation of proponent ==
Ridhima Sharma1a, François Guilleautot1, Edi Sánchez1, A. Chmyga2, J. Chercoles1, G.N. Deshko2, L.G. Eliseev3, C. Hidalgo1, P. O. Khabanov, S.M. Khrebtov2, A.D. Komarov2, A.S. Kozachek2, L.I. Krupnik2, Bing Liu1,  J. Lopez1, U. Losada1, G. Martin1, A.V. Melnikov3,4, B van Milligen1, A. Molinero1, J.L. de Pablos1, M.V. Ufimtsev5, V.N. Zenin3, A.I. Zhezhera2 

1Fusion National Laboratory, CIEMAT, 28040, Madrid, Spain
1a IST, Lisbon, Portugal
2Institute of Plasma Physics, NSC KIPT, 310108, Kharkov, Ukraine
3National Research Centre ‘Kurchatov Institute’, 123182, Moscow, Russia
4National Research Nuclear University MEPhI, 115409, Moscow, Russia
5Moscow State University, 119991, Moscow, Russia


== Details of contact person at LNF (if applicable) ==
Edi Sánchez 

== Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)==
Motivation. The heat and particle transport in fusion plasmas is generally due, in part, to turbulent process associated with small-scale instabilities driven by the inhomogeneity of density and temperature profiles in the direction normal to the magnetic surfaces. The magnitude of turbulent transport is probably the dominant parameter affecting the global confinement properties and hence the economical performance of a fusion reactor. Understanding the physics of anomalous transport in fusion devices remains one of the key issues in magnetic fusion research. 
Recent simulations have shown that in the plasma regime where the length scale of the turbulence is very small compared to the equilibrium scale set by the variation of the magnetic field, the strongest fluctuations form narrow bandlike structures on the magnetic surfaces. Thanks to this localization, the average transport through the surface is significantly smaller than that predicted at locations of peak turbulence <ref>P. Xanthopoulos et al., Physical Review X 6, 021033 (2016)</ref> <ref>. Kornilov et al., Phys of Plasmas  11 (2004) 3196</ref> <ref>E. Sánchez et al., EPS 2016</ref>. Turbulence localization remains to be experimentally confirmed and characterized in detail. 

Goals and planning. This project will concentrate in the search for turbulence asymmetries in the plasma edge (probes measurements) / core (HIBP measurements) of the TJ-II experiment and the results will be compared with simulations based on “gyrokinetic” theory with the following steps: 
1. Characterization of poloidal / toroidal asymmetries in density and potential fluctuations: Influence of radial electric fields, plasma heating and magnetic topology
2. Experimental studies of edge / core turbulence in plasmas and comparison with GK models.



 <ref>A. Einstein, Journal of Exceptional Results (2017)</ref>

== If applicable, International or National funding project or entity ==
Enter funding here or N/A

== Description of required resources ==
Required resources:
* Number of plasma discharges or days of operation: 
* Essential diagnostic systems:
* Type of plasmas (heating configuration):
* Specific requirements on wall conditioning if any:
* External users: need a local computer account for data access: yes/no
* Any external equipment to be integrated? Provide description and integration needs:

== Preferred dates and degree of flexibility ==
Preferred dates: (format dd-mm-yyyy)

== References ==
<references />

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