Pinch Discharge Research Articles

Анализ процессов формирования θ-пинча в лабораторных и природных условиях

The processes that occur during the formation of pinch discharges have been intensively studied and are being studied in programs for the implementation of controlled thermonuclear fusion, however, it is still far from a complete understanding of the mechanisms during the discharge. There are significant achievements on the way to the implementation of CTS in magnetic traps, but the final conclusion about the advantages of this solution is still far away. This work is aimed at improving one of the problems of plasma physics, namely, explaining the fact of twisting and compression of the plasma flow in the θ-pinch. At the same time, an analysis is given of the possible reasons for the formation of this type of ionized air flows in natural conditions, namely, during tornadoes and similar phenomena (tornadoes and others). As one of the arguments for such a generalization, the fact of the existence of a deafening crack on the surface of the earth at the bases of a tornado is used, which is typical only for a stream of water droplets with a high potential, that is, a vertical current. As a basis for the analysis, the results of the experimental and theoretical analysis of a periodic discharge in a liquid flow (PDLF), which were thoroughly studied earlier, were taken.

Elongated long-lived jet of dense plasma produced by a hollow laser beam

Numerical simulation of the dynamics of plasma jets planned for use for the initiation of vacuum pinch discharges has been carried out. Jets of the “laser-metal-plasma-liner” type are created by laser beams with different spatial intensity distributions, which irradiate targets of various configurations. The three variants of plasma-jets formation are considered: irradiation of a target by (i) a Gaussian beam from a neodymium laser, (ii) the same Gaussian beam incident on a hole in the target, and (iii) a beam with the intensity distribution of the Laguerre–Gaussian mode. The dynamics of spatial distributions of the electron density, jet plasma temperatures, and the target mass ablated by laser radiation is calculated. It is shown that for quite moderate laser beam energies and intensities ∼400 mJ and ∼109 W/cm2, respectively, in the second and third cases, jets are produced with the lifetime of a few tens of nanoseconds and the maximum density ∼1019 and 1021 cm−3, respectively. The use of such jets can increase the pinching efficiency and improve plasma parameters in laser-induced discharges.

Stepped pressure equilibrium with relaxed flow and applications in reversed-field pinch plasmas

The multi-region relaxed magnetohydrodynamics (MRxMHD) has been successful in the construction of equilibria in three-dimensional (3D) configurations. In MRxMHD, the plasma is sliced into sub-volumes separated by ideal interfaces, each undergoing relaxation, allowing the formation of islands and chaos. The resulting equilibrium has a stepped pressure profile across sub-volumes. The stepped pressure equilibrium code (SPEC) (S R Hudson et al, Phys. Plasmas 19, 112502 (2012)) was developed to calculate MRxMHD equilibria numerically. In this work, we have extended the SPEC code to compute MRxMHD equilibria with field-aligned flow and rotation, following the theoretical development to incorporate cross-helicity and angular momentum constraints. The code has been verified for convergence and compared to a Grad–Shafranov solver in 2D. We apply our new tool to study the flow profile change before and after the sawtooth crash of a reversed-field pinch discharge, in which data of the parallel flow is available. We find the promising result that under the constraints of cross-helicity and angular momentum, the parallel flow profile in post-crash SPEC equilibrium is flat in the plasma core and the amplitude of the flow matches experimental observations. Finally, we provide an example equilibrium with a 3D helical field structure as the favoured lower energy state. This will be the first 3D numerical equilibrium in which the flow effects are self-consistently calculated.

Characteristics of Ar K- and L-Shell Radiations in the Divergent Gas-Puff $Z$ -Pinch and the Application to Contact Photography

Ar divergent gas-puff ${Z}$ -pinch discharge with reversed polarity was performed. Spectroscopic and spatial properties of K-shell and L-shell radiations emitted from highly ionized Ar ions were investigated. It was confirmed that L-shell radiation was spreading in the axial direction, whereas K-shell radiation was emitted from a small spot. The spot size of K-shell radiation was measured, and the diameter of the spot was $34 \pm 9~\mu \text{m}$ . Small creatures were observed using the K-shell radiation emitted from the spot. Repetitive and intense point radiation source with limited spectrum was realized by the divergent gas-puff ${Z}$ -pinch.

Video Recording of Long-Lived Plasmoids near Objects Exposed to Remote and Direct Effects of High-Current Pinch Discharges

The results of observation of plasmoids that were formed during periodic discharge in a flow of liquid, in particular, water, in its surrounding space during discharge and in post-discharge, have been presented. The presence of long-lived luminous formations not only in the air, but also on the surface and above the surface of nearby objects has been noted. The reasons for the appearance of such objects and their properties, which have features not only of macro-, but also micro-objects, such as Dirac’s monopole, have been analyzed.

Correlation polarimetry for broadband magnetic fluctuation measurements.

Correlation techniques have been successfully utilized for plasma diagnostics like electron cyclotron emission to reduce measurement noise. We present the first application of such a technique to Faraday-effect polarimetry measurements on the Madison Symmetric Torus (MST). The MST far infrared (FIR) interferometer-polarimeter diagnostic utilizes 11 vertical chords with a chord separation of 7-8 cm and a heterodyne detection system for fluctuation measurements up to several hundred kHz. The planar-diode mixers viewing each chord represent independent noise sources; modifying the optical setup so that two different mixers view the same chord allows cross correlation between the two independent signals to reduce the noise floor in fluctuation measurements. In this manner, the noise floor in both interferometry and polarimetry measurements in reversed-field pinch discharges has been reduced by a factor of 20-30. The correlation polarimeter provides a sensitive measurement of broadband magnetic fluctuations.

Mechanism of soft x-ray continuum radiation from low-energy pinch discharges of hydrogen and ultra-low field ignition of solid fuels

EUV continuum radiation (10–30 nm) arising only from very low energy pulsed pinch gas discharges comprising some hydrogen was first observed at BlackLight Power, Inc. and reproduced at the Harvard Center for Astrophysics (CfA). The source was determined to be due to the transition of H to the lower-energy hydrogen or hydrino state H(1/4) whose emission matches that observed wherein alternative sources were eliminated. The identity of the catalyst that accepts 3 · 27.2 eV from the H to cause the H to H(1/4) transition was determined to HOH versus 3H. The mechanism was elucidated using different oxide-coated electrodes that were selective in forming HOH versus plasma forming metal atoms as well as from the intensity profile that was a mismatch for the multi-body reaction required during 3H catalysis. The HOH catalyst was further shown to give EUV radiation of the same nature by igniting a solid fuel comprising a source of H and HOH catalyst by passing a low voltage, high current through the fuel to produce explosive plasma. No chemical reaction can release such high-energy light. No high field existed to form highly ionized ions that could give radiation in this EUV region that persisted even without power input. This plasma source serves as strong evidence for the existence of the transition of H to hydrino H(1/4) by HOH as the catalyst and a corresponding new power source wherein initial extraordinarily brilliant light-emitting prototypes are already producing photovoltaic generated electrical power. The hydrino product of a catalyst reaction of atomic hydrogen was analyzed by multiple spectroscopic techniques. Moreover, the mH catalyst was identified to be active in astronomical sources such as the Sun, stars and interstellar medium wherein the characteristics of hydrino match those of the dark matter of the Universe.

Edge plasma properties with 3D magnetic perturbations in RFX-mod

The response of the edge plasma to a magnetic perturbation (MP) is studied in the RFX-mod device, in both reversed field pinch (RFP) and tokamak discharges. The use of spatially distributed diagnostics, in particular along the poloidal direction, allows a direct 3D characterization of the plasma. It is shown that there is a difference between the spectrum of the MP and that of different properties of the edge plasma, such as the floating potential, the electron pressure and the flow, for both RFP and tokamak plasmas. In particular, for RFP cases, even if the magnetic perturbation is mainly m = 1, with the amplitude of the m = 0 and m = 2 sidebands negligible, the connection length to the wall of the magnetic field Lcw has a more complex structure. The ergodic regions, with Lcw larger than the Kolmogorov length, are due to the interaction of both m = 1 and m = 0 modes, showing a complex and non-monochromatic behaviour along the poloidal angle. This structure of Lcw is responsible for the impure m = 1 behaviour of the plasma wall interaction, floating potential and electron pressure. Thus the helicity of the edge plasma is quite different from that of the dominant MP.

Moving cylindrical structures in pinch discharges

Moving cylindrical current structures in plasma are described in a simple model using the Davydov–Zakharov formalism. Numerical calculations confirm the existence of solutions with tangential discontinuities and the discontinuities in which the magnetic field changes its direction to opposite. Both subsonic and supersonic solutions are obtained.

Analysis of main regularities of periodic discharge passing in fluid stream

This paper describes the basic processes in the gas discharge plasma accompanying the jet of liquid flowing between the high-voltage electrode in the form of a tubular tip and the plane grounded electrode. The process is quasi-periodic due to a jet break caused by the "core" discharge on the surface of the jet and the arising shock wave. The main discharge is accompanied by one or more pinch discharges. At the bottom of a pinch in the metal there occurs a zone with ∼⃒ (100 ÷ 300) micron size and with ultra-high energy release, where the metal is hardened. The paper analyzes the cause of formation of pinches and of formation of channels in the matter of the anode which are similar to channels generated in gas during the passage of intense beams. The paper concludes that there is a self-focusing mechanism not previously studied.

Modification of the ferrous and nonferrous metals in the process of pinch discharges in the water vapor

Characteristics of a prospective method of modification of the structural-phase state and properties of materials in the process of pulsed electrical charges in water are given. Experimental results of the structural- phase changes in steels A-35, 30Kh3NMAF, and 45Kh2MFA and nonferrous metals (copper, titanium, and lead) under periodic discharge in a stream of fluid (PDSF) are presented. Formation of a compression wave with instant transition into an expansion wave creates strong local deformation and warm-up in the processed materials accompanied by formation of domains similar to metal pins in automotive rubber; rebuilding of the material structure and change in the phase state take place. The scope and extent of these changes with a fixed PDSF is determined by the nature of the alloy composition and susceptibility to structural transformations under level of pulsed exposure. Recommendations are given for the PDSF application for hardening of the material of various products, which extends the technological capabilities of modern engineering.

Dynamics of a reconnection-driven runaway ion tail in a reversed field pinch plasma

While reconnection-driven ion heating is common in laboratory and astrophysical plasmas, the underlying mechanisms for converting magnetic to kinetic energy remain not fully understood. Reversed field pinch discharges are often characterized by rapid ion heating during impulsive reconnection, generating an ion distribution with an enhanced bulk temperature, mainly perpendicular to magnetic field. In the Madison Symmetric Torus, a subset of discharges with the strongest reconnection events develop a very anisotropic, high energy tail parallel to magnetic field in addition to bulk perpendicular heating, which produces a fusion neutron flux orders of magnitude higher than that expected from a Maxwellian distribution. Here, we demonstrate that two factors in addition to a perpendicular bulk heating mechanism must be considered to explain this distribution. First, ion runaway can occur in the strong parallel-to-B electric field induced by a rapid equilibrium change triggered by reconnection-based relaxation; this effect is particularly strong on perpendicularly heated ions which experience a reduced frictional drag relative to bulk ions. Second, the confinement of ions varies dramatically as a function of velocity. Whereas thermal ions are governed by stochastic diffusion along tearing-altered field lines (and radial diffusion increases with parallel speed), sufficiently energetic ions are well confined, only weakly affected by a stochastic magnetic field. High energy ions traveling mainly in the direction of toroidal plasma current are nearly classically confined, while counter-propagating ions experience an intermediate confinement, greater than that of thermal ions but significantly less than classical expectations. The details of ion confinement tend to reinforce the asymmetric drive of the parallel electric field, resulting in a very asymmetric, anisotropic distribution.

Stationary cylindrical structures in pinch discharges

Stationary cylindrical plasma structures are numerically studied in the simple model within the Davydov-Zakharov formalism. It is shown that such solutions exist in the presence of tangential discontinuities and discontinuity in which a magnetic field, remaining unchanged in magnitude, reverses its direction. The found structures depend on two parameters: the minimum plasma density in the plasma channel and the radius at which this density is reached. The found solutions describe filaments in pinch discharges.

Soft X-ray continuum radiation from low-energy pinch discharges of hydrogen

AbstractUnder a study contracted by GEN3 Partners, spectra of high current pinch discharges in pure hydrogen and helium were recorded in the extreme ultraviolet radiation region at the Harvard Smithsonian Center for Astrophysics (CfA) in an attempt to reproduce experimental results published by BlackLight Power, Inc. (BLP) showing predicted continuum radiation due to hydrogen in the 10–30 nm region (Mills, R. L. and Lu, Y. 2010 Hydrino continuum transitions with cutoffs at 22.8 nm and 10.1 nm. Int. J. Hydrog. Energy35, 8446–8456, doi:10.1016?j.ijhydene.2010.05.098). Alternative explanations were considered to the claimed interpretation of the continuum radiation as being that emitted during transitions of H to lower-energy states (hydrinos). Continuum radiation was observed at CfA in the 10–30 nm region that matched BLP's results. Considering the low energy of 5.2 J per pulse, the observed radiation in the energy range of about 120–40 eV, reference experiments and analysis of plasma gases, cryofiltration to remove contaminants, and spectra of the electrode metal, no conventional explanation was found in the prior or present work to be plausible including contaminants, electrode metal emission, and Bremsstrahlung, ion recombination, molecular or molecular ion band radiation, and instrument artifacts involving radicals and energetic ions reacting at the charge-coupled device and H2 re-radiation at the detector chamber. Moreover, predicted selective extraordinarily high-kinetic energy H was observed by the corresponding Doppler broadening of the Balmer α line.

Digital Interferometry Applied to Transient Dense Plasmas

The work presented in this paper proposes a simple interferometric technique of recording and digital processing, which allows the obtaining of three possible interferometric records of variations at the refraction index, both in large scale and in small scale. The experimental setup basically consists of the Mach–Zehnder interferometer and a digital camera (with CMOS technology) coupled to a PC. The interferometric arrangement originally forms a pattern of very thin parallel fringes (15–20 lines/mm on the CMOS device), which could eventually be used to obtain information of the refractivity of the phase object to submillimeter scales, looking directly to the original interferogram. The digital interferometric technique shown here is for triple exposure: the first exposure contains the plasma information and the next two are only referential records (reference interferometric patterns), similar to optical holographic interferometry, but instead of each exposure occurring on the same holographic plate, the record is done in consecutive captures of a digital acquisition system. One of the referential records is captured in the same condition as the one with plasma and the other one slightly changing the incidence angle of the reference beam. Thus, with this digital interferometry technique, it is possible to obtain (for the same plasma) a microinterferogram, which is an interferogram in fringes of infinite width and an interferogram in fringes of finite width. The technique is depicted in three different cases, namely, synthetic interferograms of a Gaussian plasma profile (simulated), laser-produced plasma, and a <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$Z$</tex></formula> -pinch discharge at the SPEED2 generator. The first case describes the actual scope of the technique. For the other two pulsed plasmas, an Nd–YAG power laser (at the second harmonic, 532 nm) is used to produce the fringe pattern.

Control of Taper-Pinch Plasma by Geometrical Parameters of Capillary

We propose a new type of plasma source with a tapered pinch discharge to form dense, high-speed plasmas. Parameters controlling the behavior are indicated by considering the pinching dynamics of current sheet based on a 1-D equation of motion. The basic behavior of the plasma has been characterized as a function of those parameters using a prototype device. Results indicate that the plasma flux and velocity formed by the capillary discharge can be controlled by the initial gas density, the discharge current, and the geometry of capillary.

Matter–antimatter gigaelectron volt gamma ray laser rocket propulsion

It is shown that the idea of a photon rocket through the complete annihilation of matter with antimatter, first proposed by Sänger, is not a utopian scheme as it is widely believed. Its feasibility appears to be possible by the radiative collapse of a relativistic high current pinch discharge in a hydrogen–antihydrogen ambiplasma down to a radius determined by Heisenberg's uncertainty principle. Through this collapse to ultrahigh densities the proton–antiproton pairs in the center of the pinch can become the upper gigaelectron volt laser level for the transition into a coherent gamma ray beam by proton–antiproton annihilation, with the magnetic field of the collapsed pinch discharge absorbing the recoil momentum of the beam and transmitting it by the Moessbauer effect to the spacecraft. The gamma ray laser beam is launched as a photon avalanche from one end of the pinch discharge channel. Because of the enormous technical problems to produce and store large amounts of anti-matter, such a propulsion concept may find its first realization in small unmanned space probes to explore nearby solar systems. The laboratory demonstration of a gigaelectron volt gamma ray laser by comparison requiring small amounts of anti-matter may be much closer.

Spontaneous Generation of a Sheared Plasma Rotation in a Field-Reversedθ-Pinch Discharge

By conducting two-dimensional hybrid simulations of an infinitely long field-reversed θ-pinch discharge we discover a new type of plasma rotation, which rapidly develops at the plasma edge in the ion diamagnetic direction due to the self-consistent generation of a Hall-driven radial electric field. This effect is different from the previously identified end-shorting and particle-loss mechanisms. We also demonstrate flutelike perturbations frequently inferred in experiments and show that in the absence of axial contraction effects they may quickly alter the toroidal symmetry of the plasma.

Time-resolved hydrino continuum transitions with cutoffs at 22.8 nm and 10.1 nm

Spectra of low energy, high current pinch discharges in pure hydrogen, oxygen, nitrogen, and helium were recorded in the EUV region, and continuum radiation was only observed from hydrogen [www.blacklightpower.com/pdf/GEN3_Harvard.pdf; Int. J. Hydrogen Energy 35, 8446 (2010); Cent. Eur. J. Phys. 8, 318 (2010)]. The continuum radiation bands at 10.1 and 22.8 nm and going to longer wavelengths for theoretically predicted transitions of hydrogen to lower-energy, so called “hydrino” states, was observed first at blacklight power, Inc. (BLP) and reproduced at the Harvard center for astrophysics (CfA). Considering the low energy of 5.2 J per pulse, the observed radiation in the energy range of about 120 eV to 40 eV and reference experiments, no conventional explanation was found to be plausible, including electrode metal emission, Bremsstrahlung radiation, ion recombination, molecular or molecular ion band radiation, and instrument artifacts involving radicals and energetic ions reacting at the CCD and H2 re-radiation at the detector chamber. To further study these continuum bands assigned to hydrinos, time resolved spectra were performed that showed a unique delay of the continuum radiation of about 0.1 μs and a duration of < 2 μs following the high-voltage pulse consistent with the mechanism of recombination to form the optimal high-density atomic hydrogen in the pinch that permits the H–H interactions to cause the hydrino transitions and corresponding emission.

Formation Mechanism of Dense High-Speed Plasma Flow in Tapered Capillary Discharge

We propose a new type of plasma source using a pinch discharge in a tapered capillary, which generates a dense moving plasma by electromagnetic compression and acceleration. The axial velocity and flux of the moving plasma are controllable and can be maximized by adjusting the taper angle. The behavior can be illustrated with a simple model considering the pinching dynamics of the current sheet.