View source for TJ-II:Impurity injection by laser blow-off: influence of main ions charge/mass on impurity confinement and transport

== 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-Miranda 1, B. Zurro 1, M. Martínez 1, E. Hollmann 2, A. Baciero 1, M. Ochando 1, F. Medina 1, K.J. McCarthy 1 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 three operational days: one (compatible with other experiments) to adjust all the variables of the laser blow-off system and two days 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. 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 ==
<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).

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