High-current Low-inductance Vacuum Spark Research Articles

Coulomb Explosion of the Debye Layer As a Mechanism for the Formation of a High-Energy Ion Flow in the Plasma of a Micropinch Discharge

Flows of ions with energies on the order of megaelectronvolts, which propagate both in the axial direction and in the direction perpendicular to the symmetry axis of the discharge, are recorded in a high-current low inductance vacuum spark. Estimates based on the measurements of the total charge of suprathermal electrons emitted from the region of the waist of the current channel in the axial direction, as well as the total number of ions of the indicated energies show that the recorded ion energies correspond quite well to the value that can be achieved as a result of the Coulomb explosion of the Debye waist layer at the stage preceding the radiation compression.

A System for Registering Shadow Images of Rapid Processes in the UV Spectral Range under the Conditions of Intense Background Illumination

A system is presented for registering shadow images obtained from dense pulsed plasma with a high background illumination level, wherein an LGI-21 molecular nitrogen laser is used as an illuminator (laser pulse power 12 µW, duration 20 ns), and a modified Canon EOS 1000D camera is used as a registering unit. A micropinch discharge such as a high-current low-inductance vacuum spark (HCLIVS) has been used as the plasma object under investigation.

Determination of the Average Energy of Iron Ions in the Axial Direction of a Micropinch Discharge Using an Ion Collector

The paper is devoted to determining the average ion energy for plasma propagating in the axial direction of a high-current low-inductance vacuum spark discharge in the Pion facility. The measurements have been carried out using an ion collector. The average energy of singly of singly charged iron ions depending on the voltage across the interelectrode gap is determined.

Experimental Detection of the Signs of a Coulomb Explosion in Micropinch Plasma

A flow of ions with energies of about 3 MeV propagating in the direction perpendicular to the symmetry axis of discharge has been detected in high-current low inductance vacuum spark. Estimations show that the measured ion energies quite well correspond to the value that can be achieved as a result of “Coulomb explosion” of the waist of a plasma channel of discharge current at the stage preceding its radiation compression.

Экспериментальное обнаружение признаков кулоновского взрыва в плазме микропинча

AbstractA flow of ions with energies of about 3 MeV propagating in the direction perpendicular to the symmetry axis of discharge has been detected in high-current low inductance vacuum spark. Estimations show that the measured ion energies quite well correspond to the value that can be achieved as a result of “Coulomb explosion” of the waist of a plasma channel of discharge current at the stage preceding its radiation compression.

Visualisation of plasma induced processes in interelectrode gap of micropinch installation using laser illuminator on molecular nitrogen

The paper presents the results of researched processes in the interelectrode gap of High-current low-inductance vacuum spark (HLIV) on the "PION" system [1] by means of active laser diagnostics with visualisation of radiation field. The influence of the cathode geometry and position of the trigger system on the plasma dynamics of HLIV is considered. The regularities of the discharge for different initial conditions are established. The conditions under which the most stable plasma point is formed in space and time are determined.

Cathode configuration influence on low-inductance vacuum spark plasma dynamics

The results of studies of cathode configuration influence on high current low- inductance vacuum spark (HLVS) plasma dynamics are presented in this work. The research was carried out on “PION” installation using shadowgraphy method. Molecular nitrogen laser (λ = 337 nm) was used as a radiation source. It was determined that the HLVS behavior changes with the increase of number of discharges. In a fresh electrode system (less than 200 discharges) the dependence of constriction position on the discharge trigger position is observed during HLVS development. Also, high gradients of plasma density and secondary constrictions are observed. In a previously exploited electrode system (more than 300 discharges) HLVS behavior changes: plasma density gradients become less expressed, secondary constrictions disappear. In electrode systems with highly developed cathode surface plasma density gradient distribution pattern only slightly changes from discharge to discharge, e.g. the discharge becomes more stable.

Suprathermal electrons in a vacuum spark discharge

Results of experiments on the detection of suprathermal electron beams in the plasma of a highcurrent low-inductance vacuum spark by means of space-resolved spectral X-ray polarimetry are presented. It is shown that the observed polarization of bremsstrahlung may be caused by an ~100-keV electron beam propagating along the discharge axis from the pinching region toward the anode. The influence of the discharge initiation conditions on the parameters of the generated electron beams is analyzed.

Determination of Density of Plasma Emitted by a High-current Low-inductance Vacuum Spark Discharge using a Combined Method for Corpuscular Diagnostics

High-current low-inductance vacuum spark (HLVS) discharges are powerful sources of charged particles. Thus, wide prospects of their application are opened. In this case, it is important to bear in mind that plasma flows influence on parts of installation framework and the diagnostic equipment. In this paper the results of the integrated study of plasma flows emitted by HLVS are presented. The flow velocity was determined using a probe technique. The flow density was determined using values of gas-kinetic pressure obtained earlier by a non-contacting laser technique.

WITHDRAWN: Impact of Discharge Current Rate of High-current Low-inductance Vacuum Spark on Submicron Size Structure in Electrode Surface Area

Abstract This paper deals with the results of studying the impact of discharge current rate on electrode surface area of high-current low-inductance vacuum spark. Iron electrodes were utilized for research. It was discovered that the size of periodic structure cells on a cathode surface decreased from 600 nm (63 kA) to 150 nm (180 kA) as the discharge current rate grew along with switching to the micropinching mode. The discharge current rate exerted no significant impact on the size of structure elements on anode surface (the structure size at all currents was ∼ 400 nm).

Formation Model of Cathode Surface Structure in Contact with Plasma Flows of High-current Low-inductance Vacuum Spark

This paper presents a model describing formation of a submicron surface structure on electrodes of high-current low-inductance vacuum spark. The model is based on the development of the Kelvin-Helmholtz instability, which occurs at the boundary of tangential discontinuity between plasma and melt. This model has been used to determine the most probable lengths of instability waves, the rate of which conforms to the available sizes of structural elements on electrodes surface.

Impact of Discharge Current rate of High-current Low-inductance Vacuum Spark on Submicron size Structure in Electrode Surface Area

This paper deals with the results of studying the impact of discharge current rate on electrode surface area of high-current low-inductance vacuum spark. Iron electrodes were utilized for research. It was discovered that the size of periodic structure cells on a cathode surface decreased from 600 nm (63 kA) to 150 nm (180 kA) as the discharge current rate grew along with switching to the micropinching mode. The discharge current rate exerted no significant impact on the size of structure elements on anode surface (the structure size at all currents was ∼ 400 nm).

Influence of the electrode system on the emission characteristics of a vacuum spark

The influence of the electrode system on the emission characteristics of a high-current low-inductance vacuum spark is investigated. It is shown that the structure and composition of the spark plasma radiating in the X-ray spectral range depend substantially on the geometry and relative position of the electrodes. A mechanism related to the effect of the initial distribution of the electric field in the electrode gap is proposed to explain such a dependence. The conditions in which the radiating plasma forms from the erosion products of one or both electrodes are determined.

Optimization of micropinch plasmas produced by vacuum spark discharges

A high-current low-inductance vacuum spark was operated to produce hot micropinches in copper plasmas. In order to improve the reproducibility of the intense hard x-ray emission, different trigger modes and anode shapes were investigated. Based on the standard configuration used in many vacuum spark set-ups, the temporal jitter was reduced by a factor of eight while the spatial reproducibility of the plasma points was improved by a factor of three.