The Grid Probe as an Ionic Diagnostic Tool in Cesium Plasma

Haug, R.; Felden, M.; Schirmann, D.

doi:10.1063/1.1655793

Cited by 9 publications

(5 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Le signal, qui se propage B travers le plasma, est dCtectC au moyen d'une sonde B grille (Haug et al 1968), le dispositif expkrimental Ctant dCcrit par ailleurs (Cussenot et Felden 1969). La variation de I'amplitude et de la phase du signal r e p en fonctibn de la distance nous permet de connaitre la distance d'attCnuation 6 et de la vitesse de phase (et donc la longueur d'onde h) en fonction de la frCquence.…”

Section: Description De I'appareillageunclassified

See 1 more Smart Citation

Propagation et amortissement d'ondes acoustiques ioniques en présence de collisions ions–neutres

Cussenot¹

1975

Can. J. Phys.

View full text Add to dashboard Cite

R e~u le 13 janvier 1975 Dans un plasma d e cesium oh les collisions ions-neutres sont importantes, nous Ctudions theoriquement et experimentalement la propagation spatiale d'ondes ioniques. Un accord satisfaisant est obtenu entre la theorie et I'experience.In cesium plasma where ion-neutral collisions are important, we study, theoretically and experimentally, the spatial propagation of ion waves. Good agreement between theory and experiment is obtained.

show abstract

Section: Description De I'appareillageunclassified

“…Ainsi, la tempCrature de I'emetteur est de l'ordre de 900 K, ce qui correspond a une temptrature ionique Cquivalente (Schirmann 1968;Fabry et Cussenot 1972). Le courant de dtcharge est de I'ordre de 160 mA (sauf a 8 x Torr pour des conditions de stabilitt).…”

Section: Description De I'appareillageunclassified

Propagation et amortissement d'ondes acoustiques ioniques en présence de collisions ions–neutres

Cussenot¹

1975

Can. J. Phys.

View full text Add to dashboard Cite

show abstract

“…Discussion et conclusion. -Il est intéressant de confronter nos résultats analytico-numériques à ceux obtenus expérimentalement lors d'une étude antérieure des paramètres ioniques d'un plasma de césium par sonde à grille [9]. Cette étude menée dans un plasma obtenu par décharge et ionisation de contact avait mis en évidence le rôle séparateur de la sonde à grille ; ce rôle ainsi que les conditions dans lesquelles on peut l'obtenir, apparaissent clairement à la lumière de l'étude théorique développée dans ce papier.…”

Section: 20unclassified

Détermination de la répartition de potentiel dans l'espace interélectrode d'une sonde à grille plongée dans un plasma maxwellien

Braun¹,

Richard²,

Felden³

1973

J. Phys. France

Self Cite

View full text Add to dashboard Cite

des Aiguillettes, Case Officielle 140, 54037 Nancy, Cédex, France (Reçu le 27 septembre 1972, révisé le 1 er juin 1973) Résumé. 2014 Nous étudions différents cas possibles de répartition de potentiel entre grille et électrode collectrice d'une sonde à grille plongée dans un plasma maxwellien. Cette détermination analytico-numérique se fait à partir de l'équation de Poisson, le modèle choisi étant unidimensionnel. Les résultats exposés sont ceux obtenus dans le cas où le potentiel est monotone, puis dans celui où il présente un extrémum dans l'espace interélectrode.Abstract. 2014 We study different possible forms of the potential in the space between the grid and the collecting electrode of a grid probe immersed in a maxwellian plasma. The spatial variation of the potential is determined by a numerical-analysis solution of the Poisson equation in one dimension. The results are those obtained in the cases of a monotonic potential and of a potential with an extremum in the interelectrode space.

show abstract

“…Details of their construction and operation has been investigated by a number of authors [61,62], including some of the additional challenges of measuring ion distributions rather than electron distributions.…”

Section: Electron Energy Analyzersmentioning

confidence: 99%

“…Therefore, more particles can leak through than otherwise expected, leading to overestimation of temperature. To avoid this, it is important that the grid spacing be less than the sheath length scale [61], which is a few Debye lengths in our case where the grid is negatively biased to discriminate electrons. The effect of space charge downstream from the initial grid has also been studied [65,66].…”

Section: Electron Energy Analyzersmentioning

confidence: 99%

Experimental Study of Current-Driven Turbulence During Magnetic Reconnection

Porkoláb¹,

Egedal-Pedersen²,

Fox³

2010

View full text Add to dashboard Cite

Magnetic reconnection is an important process in magnetized plasmas ranging from the laboratory to astrophysical scales. It enables the release of magnetic energy believed to power solar flares and magnetospheric substorms. Reconnection also controls the evolution of the topology of the magnetic field, enabling deleterious instabilities, such as the sawtooth instability in fusion experiments, to transport plasma across the experiment's minor radius. Notably, simple estimates of the finite reconnection rate due to classical resistivity fail to explain the fast and explosive nature of reconnection observed in these systems. A major goal of reconnection research is to determine which mechanisms enable "fast" reconnection to occur.This thesis studied the fluctuations arising in the plasma during magnetic reconnection experiments on the Versatile Toroidal Facility (VTF), with a primary goal of testing whether "anomalous resistivity" due to micro-instabilities can speed the reconnection process. Fluctuations were studied using impedance-matched, high-bandwidth Langmuir probes. Strong, broadband fluctuations, with frequencies extending from near the lower-hybrid frequency [f LH = (f ce f ci ) 1/2 ] to the electron cyclotron frequency f ce were found to arise during the reconnection events. Based on frequency and wavelength measurements, lower-hybrid waves and Trivelpiece-Gould waves were identified. The lower-hybrid waves appear to be driven by strong perpendicular drifts or gradients which arise due to the reconnection events; an appealing possibility is strong temperature gradients. The Trivelpiece-Gould modes were found to result from kinetic, bump-on-tail instability of a runaway electron population energized by the reconnection events. Nonlinear, spiky turbulence was also observed, and attributed to the creation of "electron phase-space holes," a class of nonlinear solitary wave known to evolve from a strong beam-on-tail instability.Overall, these instabilities were found to be a consequence of reconnection, specifically the strong energization of electrons, leading to steep gradients in both coordinate-and velocity-space. However, it was not established that these modes had a strong feedback on the reconnection process: fluctuation power varied strongly between discharges and was observed to systematically trail the reconnection events. Finally, crude estimates (using quasi-linear theory) of the anomalous resistivity due to these modes did not appear large enough to substantially impact the reconnection process.

show abstract

The Grid Probe as an Ionic Diagnostic Tool in Cesium Plasma

Abstract: A plane grid probe is operated in a cesium-vapor-discharge plasma. The collected electron and ion currents are separated. The characteristic curve and its second derivative are analyzed. The densities, temperatures, and plasma potentials deduced from these curves are given and compared. .

Cited by 9 publications

References 6 publications

Propagation et amortissement d'ondes acoustiques ioniques en présence de collisions ions–neutres

Propagation et amortissement d'ondes acoustiques ioniques en présence de collisions ions–neutres

Détermination de la répartition de potentiel dans l'espace interélectrode d'une sonde à grille plongée dans un plasma maxwellien

Experimental Study of Current-Driven Turbulence During Magnetic Reconnection

Contact Info

Product

Resources

About