Micropinches in laser induced moderate power vacuum discharge

Abstract

Studies of x-ray emission from a laser induced vacuum discharge of moderate storage energy (<20 J) are examined. It is found that micropinches in the initial stage of the cathode jet expansion into the interelectrode gap are formed. Hot plasma of the micropinches emits a soft x-ray radiation and beams of accelerated electrons moving toward the anode. It is found that these phenomena occur just when both amplitude of the discharge current and energy of the initiating laser pulse lie in the specified ranges of values. The position of the micropinch within the interelectrode gap and also the intensity of the x-ray radiation and beams of the accelerated electrons emitted from the micropinch are variable over a wide range of values through changes in energy of the laser pulse and/or amplitude of the discharge current. The experimental results are compared with the data of the particle-in-cell simulations and a fair agreement is found between them.

X-ray spectra of plasma radiation from laser induced low-power vacuum discharge

“…Such radiation is detected in high-current (with a current of the order of 100 kA), discharges at a voltage of a few tens of kilovolts with stored energy in the kilojoule range, which makes their technological application more difficult. More recent studies have shown that laser-initiated vacuum discharges with a voltage of only a few kilovolts [4][5][6] or even several hundred volts [7] and with a storage energy 10 J can serve as an x-ray source in the energy range 0.5-10 keV. Such discharges, in principle, can be used for various applications.…”

Collective acceleration of ions in picosecond pinched electron beams

“…More recent studies have shown that similar ion beams are also produced with relatively low-voltage vacuum diodes (<20 keV) at a sufficiently high discharge current rise rate exceeding 10 10 A s −1 [7]. It is shown that the appearance of multi-charged ions is due to the formation in the cathodic plasma jet of an area of hot plasma on a micron scale; that is, micropinch [8]. As a reason for the acceleration of ions in the electron beam, it was proposed to capture the ions in a non-steady-state potential well formed by the space charge of the beam [9,10].…”

The influence of the conditions of laser initiation on soft X-rays emission of vacuum spark

“…The emission of soft x-ray radiation from vacuum spark discharge under the focusing of a laser pulse on the cathode is the subject of many publications [1][2][3][4] and recently the theoretical model of such a discharge was developed [5]. What caused our interest to the laser initiation of vacuum spark discharge under the focusing of the laser beam on the anode?…”