3D particle-in-cell modeling of Langmuir probe effective collecting area in magnetized plasma

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F18%3A10379290" target="_blank" >RIV/00216208:11320/18:10379290 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61389021:_____/18:00490576 RIV/68407700:21340/18:00327319

Výsledek na webu

<a href="https://doi.org/10.1088/1361-6587/aac701" target="_blank" >https://doi.org/10.1088/1361-6587/aac701</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1361-6587/aac701" target="_blank" >10.1088/1361-6587/aac701</a>

Jazyk výsledku

angličtina

Název v původním jazyce

3D particle-in-cell modeling of Langmuir probe effective collecting area in magnetized plasma

Popis výsledku v původním jazyce

Langmuir probes are a widespread tool for measurement of important plasma parameters such as electron temperature T-e, plasma electron density n(e), ion saturation current I-sat and the floating potential V-fl, which are obtained from a fit to the current-voltage (I-V) characteristic of the probe. In magnetized plasmas, the measurements can be affected by sheath expansion due to large negative bias voltages, which is addressed by the introduction of a fourth parameter to the fitting function correcting the values of all measured quantities. In order to derive the plasma density from I-sat, the understanding of probe ion collection is needed. In magnetized plasmas, the collecting area may not correspond to the real geometrical probe surface due to ion finite Larmor effects and so the derivation of I-sat (and hence n) can be rather complicated. In this work, the influence of magnetic fields on the probe effective collecting area is studied by the means of fully 3D3V particle-in-cell model SPICE3. A parameter scan based on properties of scrape-off layer plasmas at COMPASS tokamak as well as a. particular probe pin used on a horizontal reciprocating manipulator is performed. The results reveal that the presence of the probe head has a substantial effect on the outcome of the measurement as it forms a magnetic presheath at the probe location. An approximate formula for addressing the change of effective collecting area is presented and the data from the simulations are compared to measurements of COMPASS reciprocating probes and lithium beam emission spectroscopy.

Název v anglickém jazyce

3D particle-in-cell modeling of Langmuir probe effective collecting area in magnetized plasma

Popis výsledku anglicky

Langmuir probes are a widespread tool for measurement of important plasma parameters such as electron temperature T-e, plasma electron density n(e), ion saturation current I-sat and the floating potential V-fl, which are obtained from a fit to the current-voltage (I-V) characteristic of the probe. In magnetized plasmas, the measurements can be affected by sheath expansion due to large negative bias voltages, which is addressed by the introduction of a fourth parameter to the fitting function correcting the values of all measured quantities. In order to derive the plasma density from I-sat, the understanding of probe ion collection is needed. In magnetized plasmas, the collecting area may not correspond to the real geometrical probe surface due to ion finite Larmor effects and so the derivation of I-sat (and hence n) can be rather complicated. In this work, the influence of magnetic fields on the probe effective collecting area is studied by the means of fully 3D3V particle-in-cell model SPICE3. A parameter scan based on properties of scrape-off layer plasmas at COMPASS tokamak as well as a. particular probe pin used on a horizontal reciprocating manipulator is performed. The results reveal that the presence of the probe head has a substantial effect on the outcome of the measurement as it forms a magnetic presheath at the probe location. An approximate formula for addressing the change of effective collecting area is presented and the data from the simulations are compared to measurements of COMPASS reciprocating probes and lithium beam emission spectroscopy.

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

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2018

Kód důvěrnosti údajů

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

Název periodika

Plasma Physics and Controlled Fusion

ISSN

0741-3335

e-ISSN

—

Svazek periodika

60

Číslo periodika v rámci svazku

8

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

9

Strana od-do

—

Kód UT WoS článku

000435373600003

EID výsledku v databázi Scopus

2-s2.0-85050400101