scholarly journals IONOSPHERIC PLASMA VARIATIONS AFORE THE EAST OF KURIL ISLANDS EARTHQUAKE OF 13th JANUARY, 2007

2020 ◽  
Vol 4 (1) ◽  
pp. 42-46
Author(s):  
Thomas, J. E. ◽  
George, N. J. ◽  
Ekanem, A.M ◽  
Akpan, A. E.
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Langmuir Probe ◽  
Ionospheric Plasma ◽  
Statistical Approach ◽  
The State ◽  
Kuril Islands ◽  
Ion Density ◽  
Geomagnetic Indices

Plasma Analyzer (IAP) and Langmuir Probe (ISL) experiments of the DEMETER microsatellite were used to check the state of the ionosphere in the region of the M8.1 East of Kuril Islands earthquake of 13th January, 2007,30 days afore and 10 days after the event using statistical approach. The study strongly revealed that all three investigated ionospheric parameters of electron density, total ion density and electron temperature displayed unfamiliar ionospheric variations eight days before the earthquake in the daytime time half orbit measurement. To this, the electron density, total ion density and electron temperature recorded a variation of 4.09, 5.73 and -2.03 respectively. These irregularities were vetted for untrue signals using the geomagnetic indices of Kp and Dst. It was however realized that the state of the ionosphere was geomagnetically quiet during this day, hence the observed variations were seismogenic.

scholarly journals SEISMO – IONOSPHERIC INDUCED PERTURBATIONS PRIOR TO THE SEPTEMBER 28, 2007 M7.5 NORTHERN MARIANA U.S.A. GEOQUAKE FROM GPS, TEC AND DEMETER DATA

2020 ◽  
Vol 4 (1) ◽  
pp. 38-42
Author(s):  
Jewel E. Thomas
Keyword(s):  
Statistical Analysis ◽  
False Alarm ◽  
Electron Temperature ◽  
Electron Density ◽  
Seismic Event ◽  
Seismogenic Zone ◽  
Ion Density ◽  
Ionospheric Perturbations ◽  
Gps Tec ◽  
Geomagnetic Indices

Data from DEMETER (IAP and ISL sensors) and GPS (TEC), were used to decipher variations of electron density, electron temperature and ion density within the seismogenic zone of a seismic event that occurred on September 28, 2007 at Northern Mariana U.S.A, through statistical analysis. The study revealed both pre and post ionospheric perturbations from both sets of data. The observed anomalous variations were screened for false alarm using the geomagnetic indices of kp and Dst. It was observed that the abnormal TEC on -10, – 7, -3 and -2 days occurred under quiet geomagnetic conditions while all pre-seismic (-15, -10, – 9 -7 days) ionospheric variations from the DEMETER data were also obtained during quiet geomagnetic conditions suggesting them to be seismo-ionospheric induced perturbations. Interestingly, the perturbations on -10 and -7 days were simultaneously observed from both GPS and DEMETER datasets under quiet geomagnetic ionospheric conditions offering a strong pointer to the impending geo-quake.

scholarly journals Diagnostics of low-pressure capacitively coupled RF discharge argon plasma

2019 ◽  
Vol 13 (27) ◽  
pp. 76-82
Author(s):  
Kadhim A. Aadim
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Langmuir Probe ◽  
Gas Flow ◽  
Low Pressure ◽  
Gas Pressure ◽  
Rf Discharge ◽  
Electrode Gap ◽  
Probe Characteristic ◽  
Capacitively Coupled

Low-pressure capacitively coupled RF discharge Ar plasma has been studied using Langmuir probe. The electron temperature, electron density and Debay length were calculated under different pressures and electrode gap. In this work the RF Langmuir probe is designed using 4MHz filter as compensation circuit and I-V probe characteristic have been investigated. The pressure varied from 0.07 mbar to 0.1 mbar while electrode gap varied from 2-5 cm. The plasma was generated using power supply at 4MHz frequency with power 300 W. The flowmeter is used to control Argon gas flow in the range of 600 standard cubic centimeters per minute (sccm). The electron temperature drops slowly with pressure and it's gradually decreased when expanding the electrode gap. As the gas pressure increases, the plasma density rises slightly at low gas pressure while it drops little at higher gas pressure. The electron density decreases rapidly with expand distances between electrodes.

New algorithms to estimate electron temperature and electron density with contaminated DC Langmuir probe onboard CubeSat

2020 ◽  
Vol 66 (1) ◽  
pp. 148-161
Author(s):  
Shyh-Biau Jiang ◽  
Tse-Liang Yeh ◽  
Jann-Yenq Liu ◽  
Chi-Kuang Chao ◽  
Loren C. Chang ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Langmuir Probe ◽  
New Algorithms

scholarly journals Statistical analysis of C/NOFS planar Langmuir probe data

2014 ◽  
Vol 32 (7) ◽  
pp. 773-791 ◽  
Author(s):  
E. Costa ◽  
P. A. Roddy ◽  
J. O. Ballenthin
Keyword(s):  
Langmuir Probe ◽  
Ionospheric Plasma ◽  
Solar Maximum ◽  
Geomagnetic Latitude ◽  
Time Interval ◽  
Data Set ◽  
Ion Density ◽  
Forecasting System ◽  
Cycle 24 ◽  
Statistical Results

Abstract. The planar Langmuir probe (PLP) onboard the Communication/Navigation Outage Forecasting System (C/NOFS) satellite has been monitoring ionospheric plasma densities and their irregularities with high resolution almost seamlessly since May 2008. Considering the recent changes in status of the C/NOFS mission, it may be interesting to summarize some statistical results from these measurements. PLP data from 2 different years (1 October 2008–30 September 2009 and 1 January 2012–31 December 2012) were selected for analysis. The first data set corresponds to solar minimum conditions and the second one is as close to solar maximum conditions of solar cycle 24 as possible at the time of the analysis. The results from the analysis show how the values of the standard deviation of the ion density which are greater than specified thresholds are statistically distributed as functions of several combinations of the following geophysical parameters: (i) solar activity, (ii) altitude range, (iii) longitude sector, (iv) local time interval, (v) geomagnetic latitude interval, and (vi) season.

Decomposition Characteristic of Carbon Tetrafluoride Using 2.45GHz Microwave at Various Gases

2007 ◽  
Vol 544-545 ◽  
pp. 701-704
Author(s):  
Sun Yong Choi ◽  
Yuko Taguchi ◽  
Wataru Minami ◽  
Lae Hyun Kim ◽  
Hee Joon Kim
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Microwave Power ◽  
Inelastic Collision ◽  
Mean Free Path ◽  
Chamber Pressure ◽  
Ion Density ◽  
Oxygen Ion ◽  
Density Decrease ◽  
The Mean

The decomposition characteristics of CF4 with Argon or oxygen in 2.45GHz microwave has been investigated by using a Langmuir probe with variation of the microwave power and chamber pressure. For CF4/Ar and CF4/O2/Ar discharges, the ion density and the electron density decrease with increasing microwave power. The electron temperature was decreased by reducing the mean free path of electrons with increasing microwave power. Also with increasing pressure, the electron temperature increase, and ion and electron density decrease by increase of inelastic collision frequency and of collision with the walls in the chamber. The electron temperature is 13.6 ~ 5.9 [eV], the electron density is 4.4×1010 ~ 2.2×1010 [cm-3] and ion density is 5.2×1011 ~ 4×1010 [cm-3]. According as add oxygen, ion and electron density increased relatively comparing to CF4/Ar discharge. The electron temperature is 8.5 ~ 6.2 [eV], the electron and ion density is 5.1×1010 ~ 2.1×1010 [cm-3] and 3.7×1011 ~ 7.3×1010 [cm-3], respectively.

Numerical Simulation of Spacecraft Charging Attributed to Ionospheric Plasma in Polar and Equatorial Environment

2020 ◽  
Vol 52 (1) ◽  
pp. 98
Author(s):  
Nizam Ahmad ◽  
Hideyuki Usui
Keyword(s):  
Electron Temperature ◽  
Plasma Density ◽  
Ionospheric Plasma ◽  
High Energy ◽  
Plasma Electron ◽  
Equatorial Region ◽  
Plasma Properties ◽  
Ion Density ◽  
Auroral Electrons ◽  
Strong Relation

The presence of spacecraft in ionospheric plasma can change plasma properties, vice versa plasma can lead to charge buildup on spacecraft. The level of charging, through electric potential of spacecraft, initially depends on plasma density. However, simulations done on four LEO satellites, i.e. ERS 1, MIDORI, ASCA and FUSE 1, showed that charging level depends on plasma electron temperature rather than plasma density which satisfied the Boltzmann’s relation in the absence of high-energy electrons from aurora. The higher the plasma electron temperature the more spacecraft exposed to negative charging. It is assumed that plasma ions and electrons are collisionless or in Maxwellian distribution. It is found that there is no strong relation between density and charging level. Furthermore, there exists insignificant different of charging between polar and equatorial satellites. It means that the placement of satellite in polar or equatorial region, as long as the presence of auroral electrons is excluded, will suffer similar level of charging which is less than 5V (negative). Since spacecraft are exposed to negative charge, electric field generated by spacecraft potential, together with mesothermal motion effects, deflects ion trajectory into donwstream region leading to ion void region. The ion density is reduced compared to electron density, but there is no significant different of ion void feature between polar and equatorial satellites.and capacity building of beneficiaries. 

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