Speaker
Description
Energetic charged particles and plasma outflows are emitted by some transient high dense plasmas, particularly, different kinds of Z-pinches [1,2]. These emissions have been studied for producing surface modifications, implantation and/or deposition onto different substrates [2]. In this work, the axial outflows, composed of both keV-MeV ions and plasma jet, of a tungsten (W) conical wire array Z-pinch are used to modify the surface of a silicon (Si) target in a single shot basis. The experiments are performed in the Llampudken pulsed power driver (~350kA in ~350ns) [3]. To probe the plasma jet outflow, side-on UV/XUV pinhole imaging is performed, whereas ions outflows is studied using a set of Faraday cups. The substrates are analyzed using standard material science techniques including FE-SEM, EDX, XRD and AFM.
Figure 1 shows a Faraday cup signal collected 23cm above the conical array and a SEM imaging with spatially resolved EDS obtained from an irradiated Si target at similar position. The signal shows negative and positive excursions, corresponding to electrons and ions axially expelled from the array. Time-of-flight measurements indicated that characteristic W ions energy can reach up to a few MeV. Black dots on SEM/EDS image indicate tungsten presence over the target. Besides this, the irradiation of silicon reveals different kind of changes in surface morphology, such as micropores and stripes-like structures, according to their axial distance from the array. Both the characterization of tungsten plasma outflows and the effects of their interaction with silicon target will be shown and presented.
Acknowledgement: Funded by project FONDECYT 1171412. GMC and MV acknowledge CONICYT grants for graduate studies.
References:
[1] G Muñoz-Cordovez, et al, Phys Plasmas 25, 102101 (2018)
[2] H Bhuyan, et al, J Phys D: Appl Phys 40, 127 (2007)
[3] H Chuaqui, et al, Laser Part Beams 15, 241 (1997)
