Title :
Implosions of larger size wire arrays at enhanced current of 1.5–1.7 MA on zebra with LCM
Author :
Safronova, A.S. ; Esaulov, A.A. ; Kantsyrev, V.L. ; Stafford, A. ; Weller, M.E. ; Shlyaptseva, V.V. ; Zunino, H.A. ; Shrestha, I. ; Osborne, G.C. ; Keim, S.F. ; Chuvatin, A.S. ; Coverdale, C.A.
Author_Institution :
Univ. of Nevada, Reno, NV, USA
Abstract :
Experiments on Zebra with a Load Current Multiplier (LCM, which provides an enhanced current of 1.5-1.7 MA) allow the implosion of larger wire array loads than possible with the standard current of 1 MA. Advantages of the larger wire arrays include enhanced energy coupling to plasmas and better diagnostic access to observable plasma regions. Diagnostics, fielded on 10 beam lines, included PCD, XRD, and EUV detectors, X-ray/EUV spectrometers and X-ray pinhole cameras, and laser shadowgraphy. For this work, we collected and analyzed the experimental results from standard and modified triple planar wire arrays (TPWA), as well as cylindrical wire arrays (CWA). The anode-cathode gap in these experiments with LCM was 1 cm, which is half the gap used in the standard mode. For TPWAs, two outer wire planes were made out of mid-atomic-number wire material (Ni or Cu) with the inter-row gap increased from 1.5 or 3 mm (usually used at 1 MA current) up to 4.5 mm. The different designs of a central wire plane from Al were implemented to investigate its role as a magnetic field extruder to prevent the formation of closed magnetic configurations around each wire plane. Previous work has shown that larger double planar wire arrays (at a standard current) can block the inward motion of ablated plasma jets. Therefore, multi-planar wire arrays provide a new test bed to study jet formations in larger wire arrays for laboratory astrophysics. In addition, we measured higher linear radiation yield and the high-temperature precursor Al plasmas, not previously observable in experiments on Zebra at 1 Ma current. However, the observation of high-temperature precursor plasmas from Cu CWAs at enhanced current was consistent with previous findings at a standard current of 1 MA.
Keywords :
copper; explosions; nickel; plasma devices; plasma diagnostics; plasma jets; plasma temperature; wires (electric); Cu; EUV detector; EUV spectrometer; Ni; X-ray pinhole camera; X-ray spectrometer; XRD; ZEBRA; ablated plasma jet; anode-cathode gap; closed magnetic configuration; current 1.5 MA to 1.7 MA; cylindrical wire array; diagnostic access; distance 1.5 mm; distance 3 mm; enhanced energy coupling; high-temperature precursor Al plasma; implosion; inter-row gap; jet formation; laboratory astrophysics; laser shadowgraphy; linear radiation yield; load current multiplier; magnetic field extruder; mid-atomic-number wire material; multiplanar wire array; plasma region; triple planar wire array; Laboratories; Laser beams; Plasmas; Standards; USA Councils; Wires; X-ray lasers;
Conference_Titel :
Plasma Science (ICOPS), 2012 Abstracts IEEE International Conference on
Conference_Location :
Edinburgh
Print_ISBN :
978-1-4577-2127-4
Electronic_ISBN :
0730-9244
DOI :
10.1109/PLASMA.2012.6384037