Towards Fast Measurement of the Electron Temperature in the SOL of ASDEX Upgrade Using Swept Langmuir Probes

2010 ◽  
Vol 50 (9) ◽  
pp. 847-853 ◽  
Author(s):  
H.W. Müller ◽  
J. Adamek ◽  
J. Horacek ◽  
C. Ionita ◽  
F. Mehlmann ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Langmuir Probes ◽  
Fast Measurement

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.

Climatology of very high ionospheric electron temperature occurrences as observed by Swarm constellation

2021 ◽  
Author(s):  
Igino Coco ◽  
Giuseppe Consolini ◽  
Paola De Michelis ◽  
Fabio Giannattasio ◽  
Michael Pezzopane ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Physical Parameters ◽  
High Electron ◽  
Langmuir Probes ◽  
Swarm Satellites ◽  
High Electron Temperature ◽  
Physical Quantities ◽  
Very High

<p>After more than seven years in orbit, the ESA Swarm satellites have provided an already large statistics of measurements of several important physical parameters of the ionosphere. In particular, electron density and temperature are measured by pairs of Langmuir Probes, and the quality of such data is now considered good enough for many studies, either science cases or climatological characterisations. Concerning specifically the electron temperature, a rather elusive parameter which is quite difficult to correctly characterize “in situ”, and for which the past literature is not so abundant with respect to other ionospheric physical quantities, the overall distributions observed by Swarm are qualitatively consistent with expectations from theory and past observations. However, a non-negligible amount of high and very high electron temperature values is regularly observed, whose distributions and properties are not trivial. In this study we aim at characterizing such features statistically as a function of latitude, local time, and season.</p>

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.

Resolving an anomaly in electron temperature measurement using double and triple Langmuir probes

2014 ◽  
Vol 24 (1) ◽  
pp. 015017 ◽  
Author(s):  
Soumen Ghosh ◽  
K K Barada ◽  
P K Chattopadhyay ◽  
J Ghosh ◽  
D Bora
Keyword(s):  
Electron Temperature ◽  
Temperature Measurement ◽  
Langmuir Probes

FREE-FALL DIFFUSION IN A DISCHARGE AFTERGLOW

1966 ◽  
Vol 44 (11) ◽  
pp. 2615-2630 ◽  
Author(s):  
B. C. Gregory
Keyword(s):  
Electron Temperature ◽  
Free Fall ◽  
Mercury Vapor ◽  
Mean Free Path ◽  
Experimental Results ◽  
Cavity Method ◽  
Number Density ◽  
Langmuir Probes ◽  
Average Electron ◽  
Good Agreement

The afterglow decay of the number density and electron temperature of a plasma in which collisions between electrons and molecules are rare is studied both theoretically and experimentally. The theoretical approach, using the first three moment equations solved in a one-dimensional geometry, predicts non-exponential decay profiles in time for both density and temperature. Experimental results are obtained using a cylindrical mercury vapor discharge tube at pressures where the mean free path of the electrons is much larger than the transverse dimensions of the tube. The average electron number density is measured by a surface-wave cavity method and the electron temperature by means of Langmuir probes. The theoretical and experimental results are in good agreement, especially for the density decay.

Electron temperature in the upper F -region

1964 ◽  
Vol 281 (1387) ◽  
pp. 526-538 ◽  
Keyword(s):  
Electron Temperature ◽  
Modulation Depth ◽  
Satellite Telemetry ◽  
Preceding Paper ◽  
Large Change ◽  
Langmuir Probes ◽  
Low Speed ◽  
Probe Current ◽  
Voltage Sweep ◽  
Maximum Value

The Ariel I satellite, which was launched on 26 April 1962, carried two Langmuir probes to measure the density and temperature of the ionospheric electrons. The experimental technique and the physical arrangement of the probes have been described in detail in the preceding paper (Bowen, Boyd, Henderson & Willmore 1964) and only further details relevant to the measurements presented in this paper will be discussed here. The properties of the ionosphere are deduced from the first and second derivatives with respect to probe voltage of the probe current/voltage characteristic, these two quantities being transmitted in real time by the satellite telemetry system. In addition, some information from each voltage sweep of each of the probes was processed by a low-speed encoder and recorded on the satellite tape recorder for subsequent transmission when within range of a telemetry station. In this way data recorded over an entire orbit were obtained irrespective of the distribution of the telemetry stations. This paper describes the analysis of electron temperature data from the low-speed system. 2. The Storage and Processing of the Probe Measurements The low-speed encoder sampled each of two information channels from each probe during a period of 30.72 s. Since the probe sweep period was 55 s each channel was sampled once or twice during the sweep. One of the channels was used to determine the maximum modulation depth reached in the sweep of the probe curve, while the other was used to record the maximum value of the first derivative of the probe current characteristic. These quantities were determined by diode peak-reading circuits and retained in capacitor memories whose storage time was much greater than the sweep period. Temporary local storage of the information was necessary both because the presentation of the maximum value of the two parameters could not be synchronized with the encoder sampling, and because the information was sampled continuously for an interval of 0.48 s, during which time a large change in modulation depth could occur. Thus the capacitor store was required to retain the information for a time which could be as large as the interval between encoder samples.

Plasma potential and electron temperature evaluated by ball-pen and Langmuir probes in the COMPASS tokamak

2017 ◽  
Vol 59 (12) ◽  
pp. 125001 ◽  
Author(s):  
M Dimitrova ◽  
Tsv K Popov ◽  
J Adamek ◽  
J Kovačič ◽  
P Ivanova ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Plasma Potential ◽  
Langmuir Probes

Investigation of the Structure and the Plasma Parameters in a "Critical Velocity" Rotating Plasma

1976 ◽  
Vol 31 (8) ◽  
pp. 934-941 ◽  
Author(s):  
G. Himmel ◽  
E. Möbius ◽  
A. Piel
Keyword(s):  
Electron Temperature ◽  
Critical Velocity ◽  
Plasma Density ◽  
Detailed Balance ◽  
Current Transport ◽  
Langmuir Probes ◽  
Plasma Parameters ◽  
Electron Heating ◽  
First Time ◽  
Stream Instability

AbstractThe structure and the plasma parameters of a rotating plasma showing Alfvén's critical velocity were investigated for the first time by means of Langmuir probes. It was demonstrated that the occurrence of the critical velocity is causally connected with the formation of a spoke structure. The electron temperature and the plasma density were determined with local resolution by which a detailed balance concerning the plasma density and the current transport became possible. The importance of turbulent electron heating for rapid ionization at the critical velocity is emphasized. In this process the modified two-stream-instability obviously plays an outstanding role.

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