TJ-II: On the electrostatic transport driven by Alfvén modes and broadband turbulence in the plasma edge region of the TJ-II stellarator

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Experimental campaign

Spring 2022

Proposal title

TJ-II: On the electrostatic transport driven by Alfvén modes and broadband turbulence in the plasma edge region of the TJ-II stellarator

Name and affiliation of proponent

Igor Voldiner, Carlos Hidalgo Laboratorio Nacional de Fusión, CIEMAT, Madrid, Spain

Hiromi Takahashi / NIFS, Japan

David Zarsoso, Marseille University, France


Jacobo Varela, UC3M, Madrid, Spain

Details of contact person at LNF

Igor Voldiner

Description of the activity

The importance of quasi-coherent modes on transport is a growing area of research due its possible role in the development of reactor relevant scenarios. HIBP measurements have provided direct measurements of core ExB transport induced by AEs in the TJ-II stellarator [1]. It was found that the AEs contribution to the frequency resolved turbulent particle transport constitutes a significant fraction of the total flux. Interestingly although most of the AEs contribute to outwards ExB flux some modes produce inward flux.

Recently edge probes measurements that shown that electrostatic turbulence and AEs driven transport are comparable in magnitude. Whereas the turbulent transport keeps always the same radially outwards propagation, AEs can be inwards or outwards depending of the NBI co-counter configuration. In addition, edge biasing is capable to module the amplitude of ExB transport driven by plasma turbulence but has a minor impact on the ExB transport driven by AEs. These results highlight the key role of the cross-phase between density and electric field fluctuations to control the level of ExB driven transport

The goal of this proposal is to expand the present database of ExB turbulent transport driven by AEs.

International or National funding project or entity

Include funding here (grants, national plans)

Description of required resources

Required resources:

  • Number of plasma discharges or days of operation: 2
  • Essential diagnostic systems: edge probes (in feasible also HIBP)
  • Type of plasmas (heating configuration): NBI co & counter configurations
  • 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

  1. A. Melnikov et al., Nucl. Fusion 50, 084023 (2010)

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