Simulations of thermionic suppression during tungsten transient melting experiments
Identifikátory výsledku
Kód výsledku v IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F17%3A10378629" target="_blank" >RIV/00216208:11320/17:10378629 - isvavai.cz</a>
Nalezeny alternativní kódy
RIV/61389021:_____/17:00482343
Výsledek na webu
<a href="https://doi.org/10.1088/1402-4896/aa9209" target="_blank" >https://doi.org/10.1088/1402-4896/aa9209</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1088/1402-4896/aa9209" target="_blank" >10.1088/1402-4896/aa9209</a>
Alternativní jazyky
Jazyk výsledku
angličtina
Název v původním jazyce
Simulations of thermionic suppression during tungsten transient melting experiments
Popis výsledku v původním jazyce
Plasma-facing components receive enormous heat fluxes under steady state and especially during transient conditions that can even lead to tungsten (W) melting. Under these conditions, the unimpeded thermionic current density emitted from the W surfaces can exceed the incident plasma current densities by several orders of magnitude triggering a replacement current which drives melt layer motion via the J ' B force. However, in tokamaks, the thermionic current is suppressed by space-charge effects and prompt re-deposition due to gyro-rotation. We present comprehensive results of particle-in-cell modelling using the 2D3V code SPICE2 for the thermionic emissive sheath of tungsten. Simulations have been performed for various surface temperatures and selected inclinations of the magnetic field corresponding to the leading edge and sloped exposures. The surface temperature dependence of the escaping thermionic current and its limiting value are determined for various plasma parameters; for the leading edge geometry, the results agree remarkably well with the Takamura analytical model. For the sloped geometry, the limiting value is observed to be proportional to the thermal electron current and a simple analytical expression is proposed that accurately reproduces the numerical results.
Název v anglickém jazyce
Simulations of thermionic suppression during tungsten transient melting experiments
Popis výsledku anglicky
Plasma-facing components receive enormous heat fluxes under steady state and especially during transient conditions that can even lead to tungsten (W) melting. Under these conditions, the unimpeded thermionic current density emitted from the W surfaces can exceed the incident plasma current densities by several orders of magnitude triggering a replacement current which drives melt layer motion via the J ' B force. However, in tokamaks, the thermionic current is suppressed by space-charge effects and prompt re-deposition due to gyro-rotation. We present comprehensive results of particle-in-cell modelling using the 2D3V code SPICE2 for the thermionic emissive sheath of tungsten. Simulations have been performed for various surface temperatures and selected inclinations of the magnetic field corresponding to the leading edge and sloped exposures. The surface temperature dependence of the escaping thermionic current and its limiting value are determined for various plasma parameters; for the leading edge geometry, the results agree remarkably well with the Takamura analytical model. For the sloped geometry, the limiting value is observed to be proportional to the thermal electron current and a simple analytical expression is proposed that accurately reproduces the numerical results.
Klasifikace
Druh
J<sub>imp</sub> - Článek v periodiku v databázi Web of Science
CEP obor
—
OECD FORD obor
10305 - Fluids and plasma physics (including surface physics)
Návaznosti výsledku
Projekt
Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.
Návaznosti
S - Specificky vyzkum na vysokych skolach
Ostatní
Rok uplatnění
2017
Kód důvěrnosti údajů
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Údaje specifické pro druh výsledku
Název periodika
Physica Scripta
ISSN
0031-8949
e-ISSN
—
Svazek periodika
T170
Číslo periodika v rámci svazku
Nov
Stát vydavatele periodika
SE - Švédské království
Počet stran výsledku
5
Strana od-do
—
Kód UT WoS článku
000417694700014
EID výsledku v databázi Scopus
—