Strongly emissive plasma-facing material under space-charge limited regime: Application to emissive probes

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389021%3A_____%2F17%3A00474247" target="_blank" >RIV/61389021:_____/17:00474247 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1063/1.4973557" target="_blank" >http://dx.doi.org/10.1063/1.4973557</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/1.4973557" target="_blank" >10.1063/1.4973557</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Strongly emissive plasma-facing material under space-charge limited regime: Application to emissive probes

Popis výsledku v původním jazyce

A quasi-static theoretical 1D model is developed to describe the sheath structure of a strongly emissive plasma-facing material and is subsequently applied to emissive probes' experimental data - which are usually supposed to be an efficient tool to directly measure plasma potential fluctuations. The model is derived following the space-charge limited emission current model developed in Takamura et al., [Contrib. Plasma Phys. 44(1-3), 126-137 (2004)], adding the contribution of secondary emission due to back-diffusion of plasma electrons at the emitting surface. From this theory, current-voltage characteristics of emissive probes are derived. A theoretical relation between the floating potential of an emissive probe and plasma parameters is obtained and a criterion is derived to determine the threshold between the thermoemission limited current regime and space-charge limited current regime. In the space-charge limited regime, a first order expansion is then applied to the quasi-static relation to study the effect of plasma fluctuations on emissive probe measurements. Both the mean values and the fluctuations of the floating potential of an emissive probe predicted by the model, as well as the potential value at which the transition between emission current regimes occurs, are compared to three sets of experimental data obtained in two different plasma devices.

Název v anglickém jazyce

Strongly emissive plasma-facing material under space-charge limited regime: Application to emissive probes

Popis výsledku anglicky

A quasi-static theoretical 1D model is developed to describe the sheath structure of a strongly emissive plasma-facing material and is subsequently applied to emissive probes' experimental data - which are usually supposed to be an efficient tool to directly measure plasma potential fluctuations. The model is derived following the space-charge limited emission current model developed in Takamura et al., [Contrib. Plasma Phys. 44(1-3), 126-137 (2004)], adding the contribution of secondary emission due to back-diffusion of plasma electrons at the emitting surface. From this theory, current-voltage characteristics of emissive probes are derived. A theoretical relation between the floating potential of an emissive probe and plasma parameters is obtained and a criterion is derived to determine the threshold between the thermoemission limited current regime and space-charge limited current regime. In the space-charge limited regime, a first order expansion is then applied to the quasi-static relation to study the effect of plasma fluctuations on emissive probe measurements. Both the mean values and the fluctuations of the floating potential of an emissive probe predicted by the model, as well as the potential value at which the transition between emission current regimes occurs, are compared to three sets of experimental data obtained in two different plasma devices.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physics of Plasmas

ISSN

1070-664X

e-ISSN

—

Svazek periodika

24

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

12

Strana od-do

—

Kód UT WoS článku

000395395100078

EID výsledku v databázi Scopus

2-s2.0-85008951996