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Title: Study of the interrelation between the electrotechnical parameters of the plasma focus discharge circuit and the plasma compression dynamics on the PF-3 and PF-1000 facilities

Abstract

The main stages of the plasma current sheath (PCS) dynamics on two plasma focus (PF) facilities with different geometries of the electrode system, PF-3 (Filippov type) and PF-1000 (Mather type), were studied by analyzing the results of the current and voltage measurements. Some dynamic characteristics, such as the PCS velocity in the acceleration phase in the Mather-type facility (PF-1000), the moment at which the PCS reaches the anode end, and the plasma velocity in the radial stage of plasma compression in the PF-3 Filippov-type facility, were determined from the time dependence of the inductance of the discharge circuit with a dynamic plasma load. The energy characteristics of the discharge circuit of the compressing PCS were studied for different working gases (deuterium, argon, and neon) at initial pressures of 1.5–3 Torr in discharges with energies of 0.3–0.6 MJ. In experiments with deuterium, correlation between the neutron yield and the electromagnetic energy deposited directly in the compressed PCS was investigated.

Authors:
 [1];  [2];  [1]; ;  [2];  [3];  [4];  [5]
  1. Troitsk Institute for Innovation and Fusion Research (Russian Federation)
  2. National Research Centre Kurchatov Institute (Russian Federation)
  3. Institute of Plasma Physics and Laser Microfusion (Poland)
  4. Polish Academy of Sciences, Niewodniczański Institute of Nuclear Physics (Poland)
  5. Łukasiewicz University of Technology, Faculty of Electrical and Computer Engineering (Poland)
Publication Date:
OSTI Identifier:
22472338
Resource Type:
Journal Article
Resource Relation:
Journal Name: Plasma Physics Reports; Journal Volume: 41; Journal Issue: 5; Other Information: Copyright (c) 2015 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATION; ANODES; ARGON; COMPRESSION; CORRELATIONS; DEUTERIUM; ELECTRIC CURRENTS; ELECTRIC POTENTIAL; INDUCTANCE; NEON; NEUTRONS; PF-1000 DEVICE; PLASMA FOCUS; TIME DEPENDENCE

Citation Formats

Mitrofanov, K. N., E-mail: mitrkn@inbox.ru, Krauz, V. I., E-mail: krauz-vi@nrcki.ru, E-mail: vkrauz@yandex.ru, Grabovski, E. V., Myalton, V. V., Vinogradov, V. P., Paduch, M., Scholz, M., and Karpiński, L.. Study of the interrelation between the electrotechnical parameters of the plasma focus discharge circuit and the plasma compression dynamics on the PF-3 and PF-1000 facilities. United States: N. p., 2015. Web. doi:10.1134/S1063780X15040030.
Mitrofanov, K. N., E-mail: mitrkn@inbox.ru, Krauz, V. I., E-mail: krauz-vi@nrcki.ru, E-mail: vkrauz@yandex.ru, Grabovski, E. V., Myalton, V. V., Vinogradov, V. P., Paduch, M., Scholz, M., & Karpiński, L.. Study of the interrelation between the electrotechnical parameters of the plasma focus discharge circuit and the plasma compression dynamics on the PF-3 and PF-1000 facilities. United States. doi:10.1134/S1063780X15040030.
Mitrofanov, K. N., E-mail: mitrkn@inbox.ru, Krauz, V. I., E-mail: krauz-vi@nrcki.ru, E-mail: vkrauz@yandex.ru, Grabovski, E. V., Myalton, V. V., Vinogradov, V. P., Paduch, M., Scholz, M., and Karpiński, L.. Fri . "Study of the interrelation between the electrotechnical parameters of the plasma focus discharge circuit and the plasma compression dynamics on the PF-3 and PF-1000 facilities". United States. doi:10.1134/S1063780X15040030.
@article{osti_22472338,
title = {Study of the interrelation between the electrotechnical parameters of the plasma focus discharge circuit and the plasma compression dynamics on the PF-3 and PF-1000 facilities},
author = {Mitrofanov, K. N., E-mail: mitrkn@inbox.ru and Krauz, V. I., E-mail: krauz-vi@nrcki.ru, E-mail: vkrauz@yandex.ru and Grabovski, E. V. and Myalton, V. V. and Vinogradov, V. P. and Paduch, M. and Scholz, M. and Karpiński, L.},
abstractNote = {The main stages of the plasma current sheath (PCS) dynamics on two plasma focus (PF) facilities with different geometries of the electrode system, PF-3 (Filippov type) and PF-1000 (Mather type), were studied by analyzing the results of the current and voltage measurements. Some dynamic characteristics, such as the PCS velocity in the acceleration phase in the Mather-type facility (PF-1000), the moment at which the PCS reaches the anode end, and the plasma velocity in the radial stage of plasma compression in the PF-3 Filippov-type facility, were determined from the time dependence of the inductance of the discharge circuit with a dynamic plasma load. The energy characteristics of the discharge circuit of the compressing PCS were studied for different working gases (deuterium, argon, and neon) at initial pressures of 1.5–3 Torr in discharges with energies of 0.3–0.6 MJ. In experiments with deuterium, correlation between the neutron yield and the electromagnetic energy deposited directly in the compressed PCS was investigated.},
doi = {10.1134/S1063780X15040030},
journal = {Plasma Physics Reports},
number = 5,
volume = 41,
place = {United States},
year = {Fri May 15 00:00:00 EDT 2015},
month = {Fri May 15 00:00:00 EDT 2015}
}
  • The spectroscopic technique used to measure the parameters of the plasma jets generated in the plasma focus discharge and those of the plasma of the immobile gas through which these jets propagate is described. The time evolution of the intensities and shapes of spectral lines in experiments carried out with helium at the PF-3 facility was studied by means of electron-optical streak cameras. The plasma electron temperature, T ≈ 4–5 eV, was determined from the intensity ratio of two spectral lines, one of which (λ{sub 1} = 5876 Å) belongs to neutral helium, while the other (λ{sub 2} = 4686more » Å), to hydrogen-like helium ions. The plasma density at different time instants was determined from the Stark broadening of these lines in the electric fields of different nature. The plasma density is found to vary from 4 × 10{sup 14} to 2 × 10{sup 17} cm{sup −3}.« less
  • Results of measurements of soft X-ray emission with photon energies of <1 keV under conditions of a plasma focus (PF) experiment are presented. The experiments were carried out at the world’s largest PF device—the PF-3 Filippov-type facility (I ⩽ 3 MA, T/4 ≈ 15–20 µs, W{sub 0} ⩽ 3 MJ). X-ray emission from both a discharge in pure neon and with a tungsten wire array placed on the axis of the discharge chamber was detected. The wire array imploded under the action of the electric current intercepted from the plasma current sheath of the PF discharge in neon. The measuredmore » soft X-ray powers from a conventional PF discharge in gas and a PF discharge in the presence of a wire array were compared for the first time.« less
  • Plasma dynamics and radiation characteristics of the PF-1000 facility at its upper energy limit ({approx_equal} 1 MJ) were investigated by help of a number of diagnostics with ns temporal resolution. Special attention was paid to the temporal and spatial cross correlation between plasma, electron and ion beams dynamics as well as e/m radiation but in particular in relation to the neutron emission parameters. Results of these experiments are in favor of neutron emission model based on ion beam-plasma interaction with three important features: 1) plasma target is hot and confined during a few ''inertial confinement times''; 2) ions of themore » main part of the beam are magnetized and entrapped about the pinch plasma target for a longer period than the characteristic time of the plasma inductive storage system and accelerating diode existence; and 3) ion-ion collisions -- fusion and Coulomb ones -- are both responsible for neutron emission.« less
  • The present experiments were performed on the PF-1000 plasma focus device at a current of 2 MA with the deuterium injected from the gas-puff placed in the axis of the anode face. The XUV frames showed, in contrast with the interferograms, the fine structure: filaments and spots up to 1 mm diameter. In the deuterium filling, the short filaments are registered mainly in the region of the internal plasmoidal structures and their number correlates with the intensity of neutron production. The longer filamentary structure was recorded close to the anode after the constriction decay. The long curve-like filaments with spots weremore » registered in the big bubble formed after the pinch phase in the head of the umbrella shape of the plasma sheath. Filaments can indicate the filamentary structure of the current in the pinch. Together with the filaments, small compact balls a few mm in diameter were registered by both interferometry and XUV frame pictures. They emerge out of the dense column and their life-time can be greater than hundreds of ns.« less
  • This paper presents the results of the research of the influence of compressed neon, injected by the gas-puff nozzle in front of the anode axis by the deuterium current and plasma sheath on the evolution of the pinch, and neutron production at the current of 2 MA. The intense soft X-ray emission shows the presence of neon in the central region of the pinch. During the implosion and stopping of the plasma sheath, the deuterium plasma penetrates into the internal neon layer. The total neutron yield of 10{sup 10}–10{sup 11} has a similar level as in the pure deuterium shots.more » The neutron and hard X-ray pulses from fusion D-D reaction are as well emitted both in the phase of the stopping implosion and during the evolution of instabilities at the transformation of plasmoidal structures and constrictions composed in this configuration from both gases. The fast deuterons can be accelerated at the decay of magnetic field of the current filaments in these structures.« less