Measurement and data-assisted simulation of bit error rate in RQL circuits

A circuit-simulation-based method is used to determine the thermally-induced bit error rate of superconducting Single Flux Quantum logic circuits. Simulations are used to evaluate the multidimensional Gaussian integral across noise current sources attached to the active devices. The method is data-assisted and has predictive power. Measurement determines the value of a single parameter, effective noise bandwidth, for each error mechanism. The errors in the distributed networks of comparator-free Reciprocal Quantum Logic nucleate across multiple Josephson junctions, so the effective critical current is about three times that of the individual devices. The effective noise bandwidth is only 6%–23% of the junction plasma frequency at a modest clock rate of 3.4 GHz, which is 1% of the plasma frequency. This analysis shows the ways measured bit error rate comes out so much lower than simplistic estimates based on isolated devices.

Simulation of Plasma Emission in Magnetized Plasmas

The recent Parker Solar Probe observations of type III radio bursts show that the effects of the finite background magnetic field can be an important factor in the interpretation of data. In the present paper, the effects of the background magnetic field on the plasma-emission process, which is believed to be the main emission mechanism for solar coronal and interplanetary type III radio bursts, are investigated by means of the particle-in-cell simulation method. The effects of the ambient magnetic field are systematically surveyed by varying the ratio of plasma frequency to electron gyrofrequency. The present study shows that for a sufficiently strong ambient magnetic field, the wave–particle interaction processes lead to a highly field-aligned longitudinal mode excitation and anisotropic electron velocity distribution function, accompanied by a significantly enhanced plasma emission at the second-harmonic plasma frequency. For such a case, the polarization of the harmonic emission is almost entirely in the sense of extraordinary mode. On the other hand, for moderate strengths of the ambient magnetic field, the interpretation of the simulation result is less clear. The underlying nonlinear-mode coupling processes indicate that to properly understand and interpret the simulation results requires sophisticated analyses involving interactions among magnetized plasma normal modes, including the two transverse modes of the magneto-active plasma, namely, the extraordinary and ordinary modes, as well as electron-cyclotron-whistler, plasma oscillation, and upper-hybrid modes. At present, a nonlinear theory suitable for quantitatively analyzing such complex-mode coupling processes in magnetized plasmas is incomplete, which calls for further theoretical research, but the present simulation results could provide a guide for future theoretical efforts.

Wakefield stimulated terahertz radiation from a plasma grating

When a short laser pulse propagates in a corrugated plasma, its wakefield interacts with the density and electric field ripples of the plasma. In the present paper, the modulation of the plasma originates from two counter-propagating long laser pulses, i.e. the corrugated plasma can be as- sumed as a so called plasma grating. PIC (particle in cell) simulations show electromagnetic wave radiation at a frequency just above the plasma frequency when the wakefield interacts with the grating. An electromagnetic instability is proposed as the reason for the emission process. The electrostatic driver of the electromagnetic instability is the beat of wake and grating. That beat mode possess large wavenumber (originating from the small grating wavelength) and small fre- quency (of the order of the plasma frequency) when one concentrates on small ratios of the plasma modulation length to the wavelength of the wakefield. The latter situation occurs when the long laser pulses (which generate the grating) as well as the short laser pulse (which drives the wakefield) have similar frequency ω0 ≫ ωpe where ωpe is the plasma frequency. The coherent volume emission process lasts for a while. It is finally superseded by terahertz transition radiation at the boundaries of the original grating.

The Application of Microplasma in the Terahertz Field: A Review

Terahertz functional devices are essential to the advanced applications of terahertz radiation in biology and medicine, nanomaterials, and wireless communications. Due to the small size and high plasma frequency of microplasma, the interaction between terahertz radiation and microplasma provides opportunities for developing functional terahertz devices based on microplasma. This paper reviews the applications of microplasma in terahertz sources, terahertz amplifiers, terahertz filters, and terahertz detectors. The prospects and challenges of the interdisciplinary research between microplasma and terahertz technology are discussed.

Fast-sweeping Langmuir probes: what happens to the I-V trace when sweeping frequency is higher than the ion plasma frequency?

Limited particle transit time is one of several limiting factors which determines the maximum temporal resolution of a Langmuir probe. In this work, we have revisited known fast sweep Langmuir probe techniques in a uniform, quiescent multi-dipole confined hot cathode discharge with two operation scenarios: one in which the probe sweeping frequency fsweep is much lower than the ion plasma frequency fpi, another one where fsweep is much greater than fpi, respectively. This allows the investigation of the effect of limited ion-motion on I-V traces. Serious distortions of I-V traces at high frequencies, previously claimed to be ion-motion limitation effect, was not found in the degree previously claimed unless shunt resistance is sufficiently high, despite achieving a ratio of ~ 3 between the probe sweeping frequency and the ion plasma frequency. On the other hand, evidences of sheath capacitance on the I-V trace have been observed. Distortions of I-V traces qualitatively agrees with predictions of sheath capacitance response to the sweeping voltage. Additionally, techniques in fast sweep Langmuir probe are briefly discussed. The comparison between a High-speed dual Langmuir probe (HDLP) and the single probe setup shows that the capacitive response can be removed via subtracting a leakage current for the single probe setup almost as effective as using an HDLP setup, but the HDLP setup does remain advantageous in its facilitation of better recovery of weak current signal common in low plasma density situations.

Influence of Gas Type on the Laser Produced Graphite Plasma

Plasma graphite creation by a pulsed Nd: YAG laser with a wavelength of 1064nm to a target in vacuum in two cases (Argon, Air) with varied gas pressures and the resulting spectrum was diagnosed using optical emission spectroscopy for the wavelength range 320-740nm electron temperature Te and electron density ne Debye lengthλD , and plasma frequency f p were calculated. The results showed that increasing the pulse laser energy causes all plasma parameters of both gases under study to increase, as well as a rise in the emission line intensity. The ionization energy of target atoms determines the presence of an element’s atomic and ionic emission lines in the emission spectrum, increase in pressure decreases the electron temperature, and Debye length, also plasma frequency and electron density increase, as it has been proven that the type of gas does not affect the properties of plasma.

Potential Use of Cold Plasma Discharges for Frequency Reconfigurability in a Sievenpiper Mushroom Metasurface

This article presents a parametric study using full-wave simulations about the potential use of cold plasma discharges to achieve frequency reconfiguration on a Sievenpiper mushroom metasurface. The study was done by inserting plasma tubes in between the patches of the mushroom structure, in three different positions with respect to the top of the metasurface, and varying the electronic density while keeping the plasma collision frequency. The obtained results show that it is possible to shift the stop-band generated by the metasurface around 25% towards lower frequencies for an electron density value inside the tubes of 1014 cm−3, when they are placed in between the top patches of the metasurface. Additional insertion losses are exhibited when operating near the plasma frequency.

The ion transit effects on the sheath dynamics inthe intermediate radiofrequency regime: excitationsof ion-acoustic waves and solitons

The capacitively coupled plasma is investigated kinetically utilizing the particle- in-cell technique. The Argon (Ar) plasma is generated via two radio-frequencies. The plasma bulk density increases by increasing the voltage amplitude of the high frequency (≥ 13.56 MHz) which is much greater than the ion plasma frequency. The intermediate radio-frequencies ( ≈ 1 MHz) which are comparable to the ion plasma frequency causes a broadening of the ion energy distribution considerably, i.e., ions gain energies above and lower than the time-averaged energy. The good agreement between published experimental results and our theoretical calculations via the Ensemble- in-Spacetime model confirms the modulation of ions around time-averaged values. Intermediate frequencies allow ions to respond partially to the instantaneous electric field. The response of ions to the instantaneous electric field is investigated semi- analytically. The dispersion relation of the plasma sheath and bulk are derived. Stable ion acoustic modes are found. The ion-acoustic modes have two different velocities and carry energy from the sheath edge to the electrode. Also, intermediate frequencies excite solitons in the plasma sheath; the results may help to explain the ion density, flux, and energy modulation, and, consequently, the broadening of the ion energy distribution.

Propagation of new dynamics of longitudinal bud equation among a magneto-electro-elastic round rod

In this survey, structure solutions for the longitudinal suspense equation within a magneto-electro-elastic (MEE) circular judgment are extracted via the implementation of two one-of-a-kind techniques that are viewed as the close generalized technique in its field. This paper describes the dynamics of the longitudinal suspense within a MEE round rod. Nilsson and Lindau provided the visual proof of the arrival concerning longitudinal waves within thin metal films. They recommended removal of anomalies between the ports concerning emaciated ([Formula: see text] Å) Ag layers preserved on amorphous silica because of being mildly [Formula: see text]-polarized at frequency tier according to the brawny plasma frequency. Anomalies have been due to confusion over the longitudinal waves mirrored utilizing the two borders. The wavelength is connected according to this wave’s property, which is an awful lot smaller than the wave over light. The wave is outstanding only for altogether superfine films. However, metallic movies defended amorphous substrates that are intermittent within the forward levels of their evolution. This made researchers aware of the possibility on getting ready altogether few layers with a desire to discussing the promulgation about longitudinal waves up to expectation colorful each among reverberation or transport on [Formula: see text]-polarized light. The mated options via the use of generalized Riccati equation mapping method or generalized Kudryashov technique show the rule and effectiveness regarding its methods then its ability because of applying one kind of forms over nonlinear incomplete differential equations.

Possibilities of Estimating F2 Layer Peak Plasma Frequency Using HF Radiation from High Apogee Satellites over Arctic Region

Based on the results of mathematical modeling, we consider the possibility to estimate the plasma frequency F2 layer maximum of the polar ionosphere (critical frequency, foF2) using frequency-sweeping radiation from a highly elliptical spacecraft orbit in the Arctic zone. Our modeling concerning the energy problem of radio sensing consisted of analyzing wave field parameters, received field strength, and SNR on two radio paths with the distances 1900 and 2500 km along the earth’s surface, with the satellite height varying from 10,000 to 30,000 km. Radio path orientations were selected to be close to the classical limit cases of radio wave propagation in the anisotropic ionospheric plasma: quasi-longitudinal approximation and, to a large extent, the quasi-transversal one for the quiet midday and midnight conditions. As a result of these simulations and following specific spacecraft conditions, working with an optimal probing signal was proposed for the appropriate emission power for the onboard transmitter. In the inverse problem of radio sounding of an ionized media, common mathematical inaccuracy in foF2 calculated from the transionogram, frequency dependence of the probing signals magneto-ionic group delay, was estimated. Considering and founding a possible realization of the method, physical prerequisites are discussed based on the experimental data of radio waves passing the 16,000 km long radio path for Moscow–Antarctica (UAS Vernadsky).