MEASUREMENT OF LEAKAGE CURRENTS AND QUASI-STATIONARY ELECTRIC FIELD IN THE SURFACE AREA OF THE ISS RS IN THE EARTH'S IONOSPHERE

Author(s):  
Yury V. LISAKOV ◽  
Olga V. LAPSHINOVA ◽  
Nikolay M. PUSHKIN ◽  
Viktor P. KONOSHENKO ◽  
Nikolay V. MATVEEV ◽  
...  

The paper presents the results of analysis of electrical measurements performed in the space experiment "Impulse (stage 1)" on the Service module of the ISS RS. This experiment investigated the effects of the interaction of the charged component of the ionosphere to the surface of large KA, which is the ISS. This paper analyses the measurement of quasi-stationary electric field and current leakage, was, respectively, sensors of the vibration type and flat probes from the Complex control electrophysical parameters (CCEP), developed by SPJ MT. To study the dependence of measurements from the ionosphere flow direction to the surface of the ISS RS was installed two sets of sensors with the direction of the angle of "visibility" in the Nadir (towards the Earth) and to "satellite footprint " (against the velocity vector of the ISS). Carried out analysis of common regularities measurements depending on the sun-shadow environment on orbit ISS motions and depending on current geophysical dynamics of the ionosphere. Massive the measurements including more than 170 telemetric sessions were analyzed. More than 11000 hours of measurements current of leakage (or runoff current) and measurements of quasi-stationary electric field with discretization 1s and UT binding to each point were analysed. The data measurements, geophysical and orbital data were collected in an electronic album. It is shown that experimental data correlate with the crossing time of the ISS boundaries known geophysical structures: the noon Meridian, the Main ionospheric failure (MIF), the boundaries diffuse intrusion (BDI), the Equatorial Geomagnetic anomaly (EA). In this regard, despite the specificity of the ISS (the spacecraft super big sizes, the most complex spatial configuration) similar measurements, nevertheless, are quite suitable for monitoring researches of some features of an ionosphere at the level of F2 layer with a temporary scale from 1s and can be used for more detailed study of the geophysical structures and related effects in the ionosphere. In addition, the results obtained can be used for the analysis of disturbances of electromagnetic conditions near the surface of the ISS RS, for monitoring potential and currents of leakage on the surface of the ISS. Keywords: electrophysical measurements, sensors of the vibration type, flat probes, electric field, current leakage, geophysical structure, ionosphere

2013 ◽  
Vol 31 (9) ◽  
pp. 1535-1541 ◽  
Author(s):  
K.-I. Nishikawa ◽  
P. Hardee ◽  
B. Zhang ◽  
I. Duţan ◽  
M. Medvedev ◽  
...  

Abstract. We have investigated the generation of magnetic fields associated with velocity shear between an unmagnetized relativistic jet and an unmagnetized sheath plasma. We have examined the strong magnetic fields generated by kinetic shear (Kelvin–Helmholtz) instabilities. Compared to the previous studies using counter-streaming performed by Alves et al. (2012), the structure of the kinetic Kelvin–Helmholtz instability (KKHI) of our jet-sheath configuration is slightly different, even for the global evolution of the strong transverse magnetic field. In our simulations the major components of growing modes are the electric field Ez, perpendicular to the flow boundary, and the magnetic field By, transverse to the flow direction. After the By component is excited, an induced electric field Ex, parallel to the flow direction, becomes significant. However, other field components remain small. We find that the structure and growth rate of KKHI with mass ratios mi/me = 1836 and mi/me = 20 are similar. In our simulations saturation in the nonlinear stage is not as clear as in counter-streaming cases. The growth rate for a mildly-relativistic jet case (γj = 1.5) is larger than for a relativistic jet case (γj = 15).


2013 ◽  
Vol 740-742 ◽  
pp. 881-886 ◽  
Author(s):  
Hiroyuki Okino ◽  
Norifumi Kameshiro ◽  
Kumiko Konishi ◽  
Naomi Inada ◽  
Kazuhiro Mochizuki ◽  
...  

The reduction of reverse leakage currents was attempted to fabricate 4H-SiC diodes with large current capacity for high voltage applications. Firstly diodes with Schottky metal of titanium (Ti) with active areas of 2.6 mm2 were fabricated to investigate the mechanisms of reverse leakage currents. The reverse current of a Ti Schottky barrier diode (SBD) is well explained by the tunneling current through the Schottky barrier. Then, the effects of Schottky barrier height and electric field on the reverse currents were investigated. The high Schottky barrier metal of nickel (Ni) effectively reduced the reverse leakage current to 2 x 10-3 times that of the Ti SBD. The suppression of the electric field at the Schottky junction by applying a junction barrier Schottky (JBS) structure reduced the reverse leakage current to 10-2 times that of the Ni SBD. JBS structure with high Schottky barrier metal of Ni was applied to fabricate large chip-size SiC diodes and we achieved 30 A- and 75 A-diodes with low leakage current and high breakdown voltage of 4 kV.


2012 ◽  
Vol 512-515 ◽  
pp. 1263-1267
Author(s):  
Xing Gao ◽  
Guo You Gan ◽  
Li Hui Wang ◽  
Ji Kang Yan ◽  
Jian Hong Yi ◽  
...  

A novel fabricated technique, by feeding two sets of different ZnO formulations powder in a die by parts, molded only once to produce layered structure(including layer A and layer B) low-voltage ZnO varistor. The samples are examined by using energy dispersive X-ray spectroscopy (EDS), electron probe microanalysis (EPMA), scanning electron microscope (SEM) and DC electrical measurements. EDS and EPMA data indicate that doped elements only exists in layer A, The results of SEM indicate that secondary phases are formed at grain boundaries in layer A, not found in layer B. It is found that the electrical properties of low-voltage varistor are improved without reducing thickness and changing energy absorption capabilities. The higher nonlinearity coefficients, lower breakdown fields and leakage currents of layered structure low-voltage ZnO varistor, as compared to those of ZnO varistor fabricated from the conventional route. The improved current-voltage properties are attributed to the band structure difference in both sides grains, due to the different ion concentration and species in both sides of grain boundary. Layered structure varistor also has more simpler prepared technology than multilayer chip varistor.


2018 ◽  
Author(s):  
V. S. Venediktov ◽  
P. K. Tretyakov ◽  
A. V. Tupikin

2009 ◽  
Vol 1165 ◽  
Author(s):  
Helio Moutinho ◽  
Ramesh Dhere ◽  
Chun-Sheng Jiang ◽  
Mowafak Al-Jassim

AbstractWe have investigated different methods for preparing CdTe/CdS cross sections for electrical measurements, including the following: cleaving; using GaAs substrates; and sandwiching the structure between the substrate and a glass slide, and polishing with diamond discs and alumina suspension. The latter method proved to be the most reliable, with a success rate of over 90%.We investigated cross sections of CdTe/CdS samples with scanning Kelvin probe microscopy (SKPM) using two different methods: applying the alternate bias with a frequency equal to 18.5 kHz, or equal to the frequency of the second cantilever resonance peak. The results showed that using the second resonance frequency produced a smoother signal, allowing the calculation of the electric field inside the device using just the raw SKPM data.We were able to measure the distribution of the electrical potential inside working devices. Then, by taking the first derivative of the potential, we calculated the electric field and determined the location of the p-n junction.


1997 ◽  
Vol 500 ◽  
Author(s):  
Toshiaki Arai ◽  
Hideo Iiyori

ABSTRACTNovel anodized films of nitrogen-added aluminum-based alloys were proposed for use in the fabrication of gate insulators for thin-film transistors, and the effect of nitrogen addition on the anodized aluminum-based alloys was investigated. Gadolinium and neodymium were employed as alternative alloy components. The film thickness, the dielectric constant, and the roughness average of the anodized films decreased as the nitrogen content increased, and the nitrogen content was required to be lower than 20 at.%. The most improved values of the breakdown electric fields of anodized aluminum-gadolinium and aluminum-neodymium alloy were 10.1 MV/cm with 6.0 at.% nitrogen content and 9.9 MV/cm with 4.0 at.% nitrogen content, respectively. The leakage currents of the anodized films under a negative bias, which could not be suppressed by high-temperature annealing, were adequately suppressed by nitrogen addition, especially in anodized aluminum-gadolinium alloy. The current leakage of the anodized aluminum-gadolinium alloy with 6.0 at.% nitrogen content became -8E-13 A at -10 V and 150°C. This value is nearly equal to that of chemical-vapor-deposited (CVD) films.


2014 ◽  
Vol 17 (4) ◽  
pp. 109-113 ◽  
Author(s):  
Ján Novák ◽  
Ivan Vitázek

Abstract This work contains the results of measuring the electrical properties of sunflower achenes. The interest in electrical properties of biological materials resulted in engineering research in this field. The results of measurements are used for determining the moisture content, the surface level of liquid and grainy materials, for controlling the presence of pests in grain storage, for the quantitative determination of mechanical damage, in the application of dielectric heating, and in many other areas. Electrical measurements of these materials are of fundamental importance in relation to the analysis of quantity of absorbed water and dielectric heating characteristics. It is a well-known fact that electrical properties of materials, namely dielectric constant and conductivity, are affected by the moisture content of material. This fact is important for the design of many commercial moisturetesting instruments for agricultural products. The knowledge of dielectric properties of materials is necessary for the application of dielectric heating. The aim of this work was to measure conductivity, dielectric constant and loss tangent on samples of sunflower achenes, the electrical properties of which had not been sufficiently measured. Measurements were performed under variable moisture content and the frequency of electric field ranging from 1 MHz to 16 MHz, using a Q meter with coaxial probe. It was concluded that conductivity, dielectric constant and loss tangent increased with increasing moisture content, and dielectric constant and loss tangent decreased as the frequency of electric field increased.


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