Experimental observation of electron beam generation in the paraxial region of a high-current discharge due to a pinch e
- PDF / 654,376 Bytes
- 3 Pages / 612 x 792 pts (letter) Page_size
- 36 Downloads / 157 Views
MABEAM PROCESSES
Experimental Observation of Electron Beam Generation in the Paraxial Region of a HighCurrent Discharge Due to a Pinch Effect A. N. Dolgov, N. V. Zemchenkova, N. A. Klyachin, and D. E. Prokhorovich National Research Nuclear University Moscow Engineering Physics Institute, Kashirskoe sh. 31, Moscow, 115409 Russia email: [email protected] Received September 20, 2011
Abstract—The phenomenon of “runaway” of electrons in the paraxial region of a Zpinch discharge in the heavy element environment has been experimentally observed using the methods of pulsed optical shadowg raphy, Xray pinhole imaging, and timeofflight measurements. DOI: 10.1134/S1063780X12100042
INTRODUCTION A large number of theoretically feasible mecha nisms of generation of fast particle fluxes in a Zpinch have been proposed by now. However, there is no gen erally accepted pattern of accelerating processes as yet since the available experimental data (due to their fragmentariness) allow for a wide diversity of interpre tations. The notions concerning acceleration of an ion component in a plasma of a micropinch discharge seem to be an exception [1–3]. It should be noted that the experimentally revealed ion acceleration mecha nisms are not capable of providing efficient accelera tion of an electron plasma component. The authors of this paper present the results of the experimental investigations that point to the imple mentation of the electron “runaway” mechanism in a longitudinal electric field in the paraxial region of a micropinch discharge.
the radiation of the L and Kspectra of iron, respec tively) [4] and the results of shadow imaging of the spatial structure of a discharge plasma accomplished with a nitrogen laser (λ = 337 nm) with the pulse dura tion of 6 ns and a controlled delay with respect to the current profile [5], which served as an illuminator. The shadowgrams that fix the process of pinching reveal a channel of an optically dense medium extend ing from a cloud of a pinching discharge plasma to the surface of the outer (flat) electrode along the symme try axis of the discharger (Fig. 1). This structure is observed at a negative polarity of the charging voltage of a highvoltage capacitor battery that serves as a cur
EXPERIMENTAL INVESTIGATION AND ANALYSIS The experiments were carried out at the facility with a highcurrent vacuum spark [4] at discharge cur rents of up to 150 kA, the iron plasma serving as a working medium. A regular character of development of the current channel pinching until the formation of a micropinch region [5] in the first quarter of the dis charge current period in the vicinity of the current maximum is confirmed by “peculiarities” observed on the oscillogram of a signal from the magnetic probe operating in the mode of the current derivative record ing, and by the nature of timeintegral images of the Xray radiation sources obtained with the help of pin hole cameras that record the radiation in two spectral ranges, namely λ ≤ 1.8 nm and λ ≤ 0.4 nm (including 1037
Data Loading...
