Experimental study of the spatial structure of high-energy ion sources in micropinch
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Experimental Study of the Spatial Structure of HighEnergy Ion Sources in Micropinch A. N. Dolgov, N. A. Klyachin, and D. E. Prokhorovich National Research Nuclear University Moscow Engineering Physics Institute, Kashirskoe sh. 31, Moscow, 115409 Russia Received May 13, 2011; in final form, June 22, 2011
Abstract—Images of ion sources in the plasma of a micropinch discharge were recorded. The most intense ion source was found to be a ≤1mmdiameter 3mmlong anode region. The main contribution to the images is made by singlecharged ions of the plasmaforming element with energies of 10–50 keV. DOI: 10.1134/S1063780X12010035
1. INTRODUCTION In the literature, there is fairly extensive, although fragmental, information on the parameters of ion emission from the Zpinch plasma (mainly from the plasma focus). Particle methods have rarely been applied to study pinch discharges in heavyelement media. Preference is given to highresolution Xray diffraction spectros copy [1] and framecamera photography [2, 3], i.e., diagnostics that provide reliable information on the parameters of the studied object and the processes occurring in its extreme states. Along with measure ments of the absolute values of the electron density and temperature and determination of the ionization state, Xray spectroscopy turned out to be applicable to obtain information on the parameters of high energy particle fluxes and electric fields in the dis charge plasma [4–6]. As for particle methods, they are mainly applied for direct timeresolved measurements of highenergy electron beams by using Faraday cylin ders placed on the discharge axis. Such diagnostics allow one to study the dynamics of the electron beam, measure its current, and estimate the spectrum of emitted electrons from the current attenuation by the absorbing filters [1, 7]. Systematic studies of ion emis sion from the Zpinch plasma in a heavyelement medium are also expected to become an efficient diag nostic method. This is confirmed by the results obtained so far. Comparative analysis shows that the ion emission spectra recorded in the particle energy range from 30 eV to 150 keV agree well with the results of studies of the micropinch plasma by using Xray pinhole cameras, framecamera photography in the visible selfradiation, and laser shadowgraphy; mea surements of the emitted Xray energy; and theoretical calculations performed in the framework of the radia tive compression model. This allows one to reliably interpret the recorded ion spectra [3, 8, 9]. On the other hand, the origin of ions with energies of higher
than 1 MeV that were detected in [10] still remains unclear. In order to obtain more complete information of the parameters of particle emission, it is of interest to determine the spatial structure of particle sources. In this study, we used a pinhole camera to visualize pinch discharge regions that are the most intense ion sources. 2. EXPERIMENTAL DESIGN AND DISCUSSION OF THE RESULTS The experiments were carried out using a highcur
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