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.

scholarly journals Temperature and Lifetime Measurements in the SSX Wind Tunnel

2018 ◽  
Author(s):  
M. Kaur ◽  
K. D. Gelber ◽  
A. D. Light ◽  
M. R. Brown
Keyword(s):  
Wind Tunnel ◽  
Electron Temperature ◽  
Langmuir Probe ◽  
Vacuum Ultraviolet ◽  
Temperature Measurements ◽  
Local Measurement ◽  
Lifetime Measurements ◽  
Line Intensities ◽  
Proton Cooling

We describe electron temperature measurements in the SSX MHD wind tunnel using two different methods. First, we estimate Te along a chord by measuring the ratio of the C_III 97.7 nm to CIV 155 nm line intensities using a vacuum ultraviolet monochrometer. Second, we record a biasing scan to a double Langmuir probe to obtain a local measurement of Te. The aim of these studies is to increase the Taylor state lifetime, primarily by increasing the electron temperature. Also, a model is proposed to predict magnetic lifetime of relaxed states and is found of predict the lifetime satisfactorily. Furthermore, we find that proton cooling can be explained by equilibration with the electrons.

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 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.

Sub-doppler spectroscopy of the ′ v2 = 2 Rydberg level of ND3 at vacuum ultraviolet energies

1986 ◽  
Vol 101 (3) ◽  
pp. 467-482 ◽  
Author(s):  
M.N.R. Ashfold ◽  
R.N. Dixon ◽  
K.N. Rosser ◽  
R.J. Stickland ◽  
C.M. Western
Keyword(s):  
Vacuum Ultraviolet ◽  
Doppler Spectroscopy

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.

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 Spotty appearance of the solar disk as inferred from the comparaison between EUV and radio intensities

1965 ◽  
Vol 23 ◽  
pp. 109-114
Author(s):  
Z. Suemoto ◽  
F. Moriyama
Keyword(s):  
Electron Temperature ◽  
Transition Layer ◽  
Solar Disk ◽  
Sunspot Minimum ◽  
Line Intensities ◽  
Inhomogeneous Model ◽  
First Approximation

This is a revised version of the work reported to the COSPAR Symposium of 1962. In the first place, the basic components of the radio intensities ranging from 1000 MHz to 9400 MHz derived by H. Tanaka were used to establish the relation between the electron temperature and integrated number of electrons for 1960 and 1961 flights. The result justifies our former assumption that the radio intensities with which the EUV line intensities from the transition layer are to be compared should, as a first approximation, be very close to those at sunspot minimum.In the second place, the integrated numbers of electrons from the EUV line intensities were derived based on the same data as were used by Pottasch. This is to eliminate any arbitrariness in adopting parameters which are still uncertain.The result is that we still have a large amount of disagreement between the two sets of intensities in the sense that EUV line intensities are at least ten times stronger as might be inferred from the radio intensities. If one assumes an inhomogeneous model in which the solar disk is bright only in patches covering about 0.15 of its total area, the discrepancy would be eliminated.

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