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

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.

Measurement of potential variations in a dense oscillating plasma

1970 ◽  
Vol 48 (7) ◽  
pp. 918-921 ◽  
Author(s):  
Z. Zakrzewski ◽  
C. Beaudry ◽  
G. G. Cloutier
Keyword(s):  
Electron Temperature ◽  
Electric Fields ◽  
Temperature Fluctuations ◽  
Plasma Potential ◽  
Floating Potential ◽  
Reflex Discharge

When temperature fluctuations are large in a plasma, the floating potential cannot be used to calculate electric fields. This note describes a method which allows the calculation of the plasma potential as a function of time from measured values of the electron temperature and the floating potential. An application of this technique to the evaluation of electric fields in a reflex discharge is briefly outlined.

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>

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 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 Drift-Alfvén fluctuations and transport in multiple interacting magnetized electron temperature filaments

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
R. D. Sydora ◽  
S. Karbashewski ◽  
B. Van Compernolle ◽  
M. J. Poulos ◽  
J. Loughran
Keyword(s):  
Magnetic Field ◽  
Electron Temperature ◽  
Current Model ◽  
Outer Region ◽  
Wave Pattern ◽  
Plasma Potential ◽  
Magnetized Plasma ◽  
Low Energy Electrons ◽  
Convective Pattern ◽  
Set Up

The results of a basic electron heat transport experiment using multiple localized heat sources in close proximity and embedded in a large magnetized plasma are presented. The set-up consists of three biased probe-mounted crystal cathodes, arranged in a triangular spatial pattern, that inject low energy electrons along a strong magnetic field into a pre-existing, cold afterglow plasma, forming electron temperature filaments. When the three sources are activated and placed within a few collisionless electron skin depths of each other, a non-azimuthally symmetric wave pattern emerges due to interference of the drift-Alfvén modes that form on each filament’s temperature gradient. Enhanced cross-field transport from chaotic ( $\boldsymbol{E}\times \boldsymbol{B}$ , where $\boldsymbol{E}$ is the electric field and $\boldsymbol{B}$ the magnetic field) mixing rapidly relaxes the gradients in the inner triangular region of the filaments and leads to growth of a global nonlinear drift-Alfvén mode that is driven by the thermal gradient in the outer region of the triangle. Azimuthal flow shear arising from the emissive cathode sources modifies the linear eigenmode stability and convective pattern. A steady-current model with emissive sheath boundary predicts the plasma potential and shear flow contribution from the sources.

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