Langmuir Probes in Plasma with Anisotropic Velocity Distributions

1972 ◽  
Vol 50 (4) ◽  
pp. 410-413
Author(s):  
H. Tokutaka ◽  
D. G. Frood
Keyword(s):  
Distribution Function ◽  
Electron Temperature ◽  
Flat Plate ◽  
Langmuir Probe ◽  
Langmuir Probes ◽  
Simple Manner ◽  
Velocity Anisotropy ◽  
Modulation Technique ◽  
Principal Axes

The electron temperature measured by a flat-plate Langmuir probe in a plasma with an elliptically anisotropic distribution function is shown to be related in a simple manner to the electron temperatures on the principal axes of the distribution function and to the orientation of the plate with respect to these axes. Velocity anisotropy would be most readily measured using the AC modulation technique in conjunction with a rotatable probe.

scholarly journals Use of Computer Experiments to Study the Current Collected by Cylindrical Langmuir Probes

2016 ◽  
Vol 3 (3) ◽  
pp. 105-109
Author(s):  
A. Tejero-del-Caz ◽  
J. M. Díaz-Cabrera ◽  
J. I. Fernández Palop ◽  
J. Ballesteros
Keyword(s):  
Electron Temperature ◽  
Langmuir Probe ◽  
Computer Experiments ◽  
Temperature Ratio ◽  
Langmuir Probes ◽  
Particle In Cell ◽  
Probe Radius ◽  
Cell Simulation ◽  
Cylindrical Langmuir Probe

A particle-in-cell simulation has been developed to study the behaviour of ions in the surroundings of a negatively biased cylindrical Langmuir probe. Here, we report our findings on the transition between radial and orbital behaviour observed by means of the aforementioned code. The influence of the ion to electron temperature ratio on the transition for different dimensionless probe radius is discussed. Two different behaviours have been found for small and large probe radii.

scholarly journals Dayside electron temperature and density profiles at Mars: First results from the MAVEN Langmuir probe and waves instrument

2015 ◽  
Vol 42 (21) ◽  
pp. 8846-8853 ◽  
Author(s):  
R. E. Ergun ◽  
M. W. Morooka ◽  
L. A. Andersson ◽  
C. M. Fowler ◽  
G. T. Delory ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Langmuir Probe ◽  
Density Profiles ◽  
First Results

scholarly journals Effect of the gas puff location on the divertor plasma properties in COMPASS tokamak

2020 ◽  
Vol 1492 (1) ◽  
pp. 012003
Author(s):  
M Dimitrova ◽  
M Tomes ◽  
Tsv Popov ◽  
R Dejarnac ◽  
J Stockel ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Vacuum Chamber ◽  
Plasma Potential ◽  
Saturation Current ◽  
Langmuir Probes ◽  
Plasma Parameters ◽  
Plasma Properties ◽  
Low Field ◽  
Saturation Current Density ◽  
Deuterium Gas

Abstract Langmuir probes are used to study the plasma parameters in the divertor during deuterium gas puff injection on the high- (HFS) or low-field sides (LFS). The probe data were processed to evaluate the plasma potential and the electron temperatures and densities. A difference was found in the plasma parameters depending on the gas puff location. In the case of a gas puff on the LFS, the plasma parameters changed vastly, mainly in the inner divertor – the plasma potential, the ion saturation-current density and the electron temperature dropped. After the gas puff, the electron temperature changed from 10-15 eV down to within the 5-9 eV range. As a result, the parallel heat-flux density decreased. At the same time, in the outer divertor the plasma parameters remained the same. We thus concluded that using a gas puff on the LFS will facilitate reaching a detachment regime by increasing the density of puffed neutrals. When the deuterium gas puff was on the HFS, the plasma parameters in the divertor region remained almost the same before and during the puff. The electron temperature decreased with just few eV as a result of the increased amount of gas in the vacuum chamber.

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.

scholarly journals Electron temperature in nighttime sporadic E layer at mid-latitude

2008 ◽  
Vol 26 (3) ◽  
pp. 533-541 ◽  
Author(s):  
K.-I. Oyama ◽  
T. Abe ◽  
H. Mori ◽  
J. Y. Liu
Keyword(s):  
Heat Source ◽  
Electron Temperature ◽  
Physical Parameter ◽  
Langmuir Probe ◽  
Present Theory ◽  
Height Range ◽  
Neutral Temperature ◽  
Sporadic E Layer ◽  
Sporadic E ◽  
Parameter Values

Abstract. Electron temperature in the sporadic E layer was measured with a glass-sealed Langmuir probe at a mid-latitude station in Japan in the framework of the SEEK (Sporadic E Experiment over Kyushu)-2 campaign which was conducted in August 2002. Important findings are two fold: (1) electron temperature and electron density vary in the opposite sense in the height range of 100–108 km, and electron temperature in the Es layer is lower than that of ambient plasma, (2) electron temperature in these height ranges is higher than the possible range of neutral temperature. These findings strongly suggest that the heat source that elevates electron temperature much higher than possible neutral temperature exists at around 100 km, and/or that the physical parameter values, which are used in the present theory to calculate electron temperature, are not proper.

scholarly journals Temperature and Lifetime Measurements in the SSX Wind Tunnel

Plasma ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 229-241 ◽  
Author(s):  
Manjit Kaur ◽  
Kaitlin Gelber ◽  
Adam Light ◽  
Michael Brown
Keyword(s):  
Simple Model ◽  
Wind Tunnel ◽  
Electron Temperature ◽  
Langmuir Probe ◽  
Vacuum Ultraviolet ◽  
Lifetime Measurements ◽  
Line Intensities ◽  
Thermal Equilibration ◽  
Local Measurements ◽  
Doppler Spectroscopy

We describe ion and electron temperature measurements in the Swarthmore Spheromak Experiment (SSX) MHD wind tunnel with the goal of understanding limitations on the lifetime of our Taylor-state plasma. A simple model based on the equilibrium eigenvalue and Spitzer resistivity predicted the lifetime satisfactorily during the first phase of the plasma evolution. We measured an average T e along a chord by taking the ratio of the C I I I 97.7 nm to C I V 155 nm line intensities using a vacuum ultraviolet (VUV) monochromator. We also recorded local measurements of T e and n e using a double Langmuir probe in order to inform our interpretation of the VUV data. Our results indicated that the plasma decayed inductively during a large part of the evolution. Ion Doppler spectroscopy measurements suggested that ions cooled more slowly than would be expected from thermal equilibration with the electrons, which maintained a constant temperature throughout the lifetime of the plasma.

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
Sign in / Sign up

Export Citation Format

Share Document