TJ-II: SOL Temperature profiles using RFA role of edge radial electric fields

Experimental campaign

Spring 2022

Proposal title

TJ-II: SOL Temperature profiles using RFA: role of edge radial electric fields

Name and affiliation of proponent

Igor Nedzelskiy, Carlos Silva (IST)

Mark Koepke (UWV)

Igor Voldiner, Daniel Carralero, Gregorio Martin, J. L. de Pablos, Carlos Hidalgo (CIEMAT)

Details of contact person at LNF

Igor Voldiner

Description of the activity

Rational: The evolution of the ion temperature (Ti) has been previously investigated using RFA measurements during the transition from the electron-root to the ion-root in the Scrape-Off-Layer (SOL) region in TJ-II. As line-averaged density increases above a threshold value, the edge radial electric field reverses from positive to negative values, as predicted by the neoclassical electron-to-ion root transition. Results show a significant decrease in the SOL ion temperature (in the range of 10 – 20 eV) concomitant with the reduction of edge-SOL turbulence spreading controlled by edge radial electric fields [1].

Research goals: The goal of the experiment would be to study the influence of edge radial electric fields on SOL Ti profiles. With this goal it is proposed to measure the radial profile of Ti in electron and ion root scenarios in ECRH plasmas and NBI regimes.

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: 4 days
  • Essential diagnostic systems: Langmuir probes, RFA, Doppler Reflectometry
  • Type of plasmas (heating configuration): ECRH and NBI
  • 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)


  1. Gustavo Grenfell et al., NF(2020)

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