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Title: Study of instability formation and EUV emission in thin liners driven with a compact 250 kA, 150 ns linear transformer driver

A compact linear transformer driver, capable of producing 250 kA in 150 ns, was used to study instability formation on the surface of thin liners. In the experiments, two different materials, Cu and Ni, were used to study the effect of the liner's resistivity on formation and evolution of the instabilities. The dimensions of the liners used were 7 mm height, 1 mm radius, and 3 μm thickness. Laser probing and time resolved extreme ultraviolet (EUV) imaging were implemented to diagnose instability formation and growth. Time-integrated EUV spectroscopy was used to study plasma temperature and density. A constant expansion rate for the liners was observed, with similar values for both materials. Noticeable differences were found between the Cu and Ni instability growth rates. The most significant perturbation in Cu rapidly grows and saturates reaching a limiting wavelength of the order of the liner radius, while the most significant wavelength in Ni increases slowly before saturating, also at a wavelength close to the liner radius. Evidence suggests that the instability observed is the well-known m = 0 MHD instability. However, upon comparing the instability evolution of Cu and Ni, the importance of the resistivity on the seeding mechanism becomes evident. A comparison of end-on and side-on EUV emissionmore » possible indicates the formation of precursor plasma, where it has been estimated using EUV spectroscopy that the precursor plasma temperature is approximately 40 eV with ion density of order 10{sup 19} cm{sup −3}, for both materials.« less
Authors:
; ; ;  [1] ;  [2]
  1. Center for Energy Research, University of California San Diego, La Jolla, California 92093 (United States)
  2. Facultad de Física, Pontificia Universidad Católica de Chile, Ave. Vicuña Mackena 4860, Macul, Santiago (Chile)
Publication Date:
OSTI Identifier:
22252012
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COMPARATIVE EVALUATIONS; ELECTRON TEMPERATURE; EXTREME ULTRAVIOLET RADIATION; INSTABILITY GROWTH RATES; ION TEMPERATURE; LINERS; MAGNETOHYDRODYNAMICS; MATERIALS; PERTURBATION THEORY; SPECTROSCOPY; THICKNESS; TIME RESOLUTION; TRANSFORMERS; WAVELENGTHS