Ultrahigh Frequency Discharge Research Articles

On the Role of Runaway Electrons in Stimulating the RF Breakdown and Plasma Formation in Torsatrons Uragan-3M, Uragan-2M

We consider a scenario of the initial stage of the RF breakdown of a working gas in torsatrons Uragan-3M and Uragan-2M and the roles of runaway electrons in this process. In our previous works, we studied only the acceleration factor of the breakdown process which occurs, when the intensity of the flow of runaway electrons increases due to the stimulation by an additional ultrahigh-frequency discharge at the front edge of a magnetic field pulse. This work attempts to describe the individual phenomena that accompany the initial stage of plasma formation in the confinement areas of torsatrons Uragan-3M and Uragan-2M in the presence of the flow of runaway electrons.

Fabrication of nanostructured materials in ultrahigh-frequency discharge plasma

Erosion of electrode material in ultrahigh-frequency (UHF) discharge plasma was investigated as a method of obtaining highly disperse powders and complex multiphase systems. The effect of the flow rate of the plasma-forming gas on electrode erosion was investigated. Data are reported on the effect of the current on electrode erosion in conditions of UHF-discharge plasma. The products or erosion obtained were characterized and investigated by scanning electron microscopy and other methods. The possible areas of application of these materials in science and technology are examined.

Specific features of disposal of sulfuric acid solutions resulted from magnesium silicate decomposition

The photocatalytic activity of crystalline titania nanopowders synthesized in a stream of ultrahigh-frequency discharge oxygen-containing low-temperature plasma was assessed. To this end, oxidation of an organic dye was carried out in UV-irradiated aqueous suspensions of TiO2 at different concentrations and varied irradiation times.

A technique for assessment of the photocatalytic properties of plasmochemically synthesized crystalline TiO2 nanopowders

The photocatalytic activity of crystalline titania nanopowders synthesized in a stream of ultrahigh-frequency discharge oxygen-containing low-temperature plasma was assessed. To this end, oxidation of an organic dye was carried out in UV-irradiated aqueous suspensions of TiO2 at different concentrations and varied irradiation times.

Profile control of the large area ribbon beam ion source using 500 MHz ultrahigh frequency discharge

This article is concerned with the method of controlling the large area ribbon beam profile produced by the same extraction electrode size ion source. We used a bucket type large area ion source with 500 MHz ultrahigh frequency (UHF) discharge for the plasma production. The size of the ion source is comparable to one wavelength of 500 MHz rf. As the UHF wave propagates in the plasma, electrons are accelerated by the rf fields along the multicusp magnetic field produced by the peripheral permanent magnets set on the outer surface of the plasma chamber. We used several entrances of the UHF wave around the plasma chamber. We can control the ion beam profile by adjusting the size of the entrance hole. With this control, less than 2% of uniformity of the large area ion beam of 120 mm×220 mm is achieved for the source gases such as diborane, phosphine, and arsine.

Doppler-Shifted Laser-Induced Fluorescence Diagnostics of an Ultrahigh-Frequency Discharge Plasma

Ultrahigh-frequency (UHF) discharge plasma, as well as electron cyclotron resonance (ECR) plasma and inductively coupled plasma (ICP), is diagnosed in a series of measurements of metastable ion (Ar+, Cl+) and neutral (Ne) temperatures by Doppler-shifted laser-induced fluorescence. Cl+ temperature is found to be lower in UHF plasma and ICP than in ECR plasma. In UHF plasma, the ion temperature weakly depends on both pressure and power, suggesting that plasma uniformity is insensitive to these external parameters. Magnetic multipole confinement enables the production of a stable UHF plasma even at pressures below 0.13 Pa where the plasma cannot be produced without the confinement. In this pressure region, Cl+ temperature is decreased to ≈0.1 eV.

Partial discharge diagnostics for gas insulated substations

A defect such as a free metallic particle or stress-raising edge on an electrode could lead to breakdown in a gas insulated substation (GIS), but may be detected by the partial discharges it generates. Of the various detection means available, most success has been achieved with either acoustic transducers to detect sound waves from the discharge, or electrical couplers to pick up the ultra-high-frequency (UHF) signals generated inside the GIS chambers. All new GIS in the UK are fitted with internal couplers for UHF monitoring, and two examples of continuous monitoring schemes on 400 kV GIS at nuclear power stations are described. Further developments, which are already well advanced, include specifying and measuring the coupler characteristics, making use of expert systems to interpret the UHF discharge data, and extending the monitoring system to include the performance of circuit breakers and other equipment. >

2180. Investigation of stationary ultrahigh frequency discharge excited in the diffusion regime: A I Maksimov et al,Zh Tekh Fiz,45 (4), 1975, 783–788 ( in Russian)

2180. Investigation of stationary ultrahigh frequency discharge excited in the diffusion regime: A I Maksimov et al,Zh Tekh Fiz,45 (4), 1975, 783–788 ( in Russian)

499. Relationship between the coefficients of longitudinal and transverse diffusion in the argon plasma of an ultrahigh frequency discharge: V N Budnikov et al, Zh Tekh Fiz, 41 (6), 1971, 1138–1140 ( in Russian)

499. Relationship between the coefficients of longitudinal and transverse diffusion in the argon plasma of an ultrahigh frequency discharge: V N Budnikov et al, Zh Tekh Fiz, 41 (6), 1971, 1138–1140 ( in Russian)

1472. Investigation of ultrahigh frequency discharge parameters by a microwave method: E V Belousov and A P Motornenko, Zh Tekh Fiz, 41 (5), 1971, 944–951 ( in Russian)

1472. Investigation of ultrahigh frequency discharge parameters by a microwave method: E V Belousov and A P Motornenko, Zh Tekh Fiz, 41 (5), 1971, 944–951 ( in Russian)

1167. Conditions for tangential secondary electron ultrahigh frequency discharge formation: V P Sazonov et al, elektron tekh elektron SVCh, 12, 1970, 3–13 ( in Russian).

1167. Conditions for tangential secondary electron ultrahigh frequency discharge formation: V P Sazonov et al, elektron tekh elektron SVCh, 12, 1970, 3–13 ( in Russian).

1671. Some peculiarities of a stationary ultra high frequency discharge in a magnetic field: V E Golant et almZh Tekh Fiz,36(6), June 1966, 1144–1146 (in Russian)

This work is a continuation of our study of a cataractous human eye lens removed after phacoemulsification surgery. There are clear differences in the lens colors that allowed for distinguishing two opaque phases in the obtained biological material: the white- and yellow-phase. The Raman spectroscopy and 2D correlation spectroscopy method were used to trace a pathologically altered human cataract lens at a molecular level. Although the Raman spectra of these two phases are relatively similar, taking advantage of 2D correlation, and considering time as an external perturbation, the synchronous and asynchronous spectra were obtained showing completely different patterns. Prominent synchronous auto-peaks appear at 3340, 2920, 1736, 1665 and 1083 cm−1 for the white-, and at 2929 and 1670 cm−1 for the yellow phase. The white phase is characterized by intensive asynchronous peaks at −(2936, 3360), −(1650, 1674) and +(1620,1678). The modifications in the water contained in the white phase structure are ahead of the changes in the protein (CH3-groups), furthermore changes in β-conformation are asynchronous with respect to the α-structure.The yellow phase demonstrates asynchronous peaks: +(2857, 2928), +(1645,1673), +(1663, 1679), and +(1672,1707). These illustrate concomitant modifications in the β- and unordered conformation. Both forms of cataractous human eye lens, white- and yellow-phases, are degenerate forms of the eye lens proteins, both are arranged in a different way. The main differences are observed for the amide I, methyl, methylene and OH vibrational band region. The effect of Asp, Glu and Tyr amino acids in cataractous lens transformations was observed.