diode laser-induced fluorescence (lif)measurements of metastable argon ions in a magnetized...

Diode laser-induced fluorescence (LIF)measurements of metastable argon ions in a magnetized inducti

vely coupled plasma （ ICP ）

报告人：李长君

组员：周涛涛 刘皓东 李长君 吴凯 任杰 刘沛航

introductionmetastable argon ion (in magnetized

inductively coupled plasma)LIF

velocity distribution functions

metastable ion density and temperature

construct a model

theoretical model for Tion

MICP chamber

fluorescence (442.72nm)

laser (668.61nm)

plasma(generated at 13.56MHz)

Pyrex tubestainless steel chamber

grounded electrode

single-turn antenna

bandpass optical filter (1nm bandwidth) PM tubefiber

Langmuir probe

Measured metastable ion velocity distribution function

FWHMT

arean

i

mi

Theoretical model for metastable ion density

Metastable ion density vs electron density when rf power changes

neutrals ions

)1(1

103

101,1.0216

mTorrmf

cm

scmLeVT

CT

cross

i

e

，

zero-dimensional rate equation

electron-impact excitation coefficient

Electron temperature, electron density, and plasma potential as a function of pressure, rf power, and B field.

Comparison between measured metastable ion density and calculated metastable ion density as a function of pressure, power, and B field. Bothdensities are normalized to 1

ni=107~109cm-3

dc bias effect

• ion heating sources: electron-ion collisions, the acceleration from spatial potential, and wave-particle interactions.

biasVVV p

Theoretical model for ion temperaturespatial potential →additional vdrift

collide with other ions and neutrals

transfer energy

increase Ti and Tn

charge exchange wiith a neutral

convert to neutral kinetic energy

Ti and Tn ← energy balance equation

electron collisions the acceleration from spatial potential

neutral collisionswall collisions

electrons and ions lose by the neutral collisions

wall collisions