TJ-II:Proposal template
Experimental campaign
2017 Spring
Proposal title
Impurity injection by laser blow-off: influence of main ions charge/mass on impurity confinement and transport
Name and affiliation of proponent
B. López-Miranda1, B. Zurro1, M. Martínez1, E. Hollmann2, A. Baciero1, M. Ochando1, F. Medina1, K.J. McCarthy1 and TS and TJ-II Team.// 1 Laboratorio Nacional de Fusión, CIEMAT, Madrid, Spain. 2 University of California, San Diego, La Jolla, CA, USA.
Details of contact person at LNF (if applicable)
B. López-Miranda: belen.lopez@ciemat.es
Description of the activity, including motivation/objectives and experience of the proponent (typically one-two pages)
Motivation. In previous experiments of impurity confinement in TJ-II plasmas we have investigated the behaviour of impurity confinement with the mass composition of the main ions and with charge/mass of the injected impurities [1]. Now we want to extend our study to He plasmas.
Proposal. Within the present proposal, we plan to inject light and heavy impurities into TJ-II ECRH plasmas by means of laser blow-off. We plan to study the behaviour of impurity confinement with the charge/mass of the main ions on the relaxation of emission of light and heavy impurities injected in TJ-II. For that purpose we want discharges in He and study the impurity confinement as a function of effective mass.
If applicable, International or National funding project or entity
This work was funded by the Spanish “MINECO” under Grant No. ENE2014-56517-R. B.L.M. would like to acknowledge her scholarship, Grant No. BES-2015-075704.
Description of required resources
Required resources:
- Number of plasma discharges or days of operation: We would need at least two operational days: one (compatible with other experiments) to adjust all the variables of the laser blow-off system and another day to perform the experiment.
- Essential diagnostic systems: Main diagnostics will be radiation diagnostics (bolometers, X-rays, VUV spectrometer, etc.) and ECR radiometer data as well as other diagnostics with good time resolution.
- Type of plasmas (heating configuration): We need standard configuration plasmas (100_44_64).
- Specific requirements on wall conditioning if any:
1. We want discharges in He in order to study the impurity confinement as a function of effective mass. 2. We need discharges with solely ECRH and good control with constant density along discharges with at least three levels of ECRH power. Lower densities appear to give more stable target plasmas; however, we wish plasma electron densities that are sufficiently high to ensure good Thomson scattering profiling of the target plasma.
- External users: need a local computer account for data access: N
- Any external equipment to be integrated? Provide description and integration needs: N
Preferred dates and degree of flexibility
Preferred dates: (XX-03-2017) We would like to perform the experiment during March 2017.
References
1. ZURRO B., HOLLMANN E., BACIERO A., OCHANDO M.A., MEDINA F., McCARTHY K.J. et al., “Transport studies using laser blow-off injection of low-Z trace impurities injected into the TJ-II stellarator”, Nuclear Fusion 51 (2011) 063015 (9pp).