lect-p等離子體源離子注入

Simulation

methods

for

PWIFor

different

issues,

different

methods

areapplied.Typical

Applications等離子體源離子注入Separation

by

plasma

implantation

of

oxygen--SPIMOXto

form

the

silicon-on-insulator

(SOI)

structure.材料表面改性等ytical

model,Sheath

evolutionSee

Liebermann’s

bookComparison

between

Numerical

andytical

ModelsPressure:

0.5

mTorr;

working

gas:

ArSeparation:25

cm.Initial:

ve,

vi

full-Maxwellian

distribution;Te=

5eV,

plasma

potential,

20V,x=

0.025

cm,

t=

2.0

×

10?11

s,

1.0×10?9

sN=

5.0×105

for

electrons

and

ions

each.Vapplied=

10

kVWaveform:

trapezoidal

witha

rise

time

of10

ns,

aduration

of3μsSimulation

methods

for

implanted

ions

in

solidEnergy

ions

range:

>

10

keV為了

材料改性（濃度分布）的結(jié)果，需要了解：PSII鞘層的特性（包括離子轟擊到表面的能量）離子在材料中的能量損失離子在材料中的傳輸（射程分布、濃度分布）材料的表面層的原子運(yùn)動(dòng)情況離子在固體中運(yùn)動(dòng)過(guò)程的計(jì)算機(jī)模擬模擬離子在固體中運(yùn)動(dòng)的方法有三種：數(shù)值求解Boltzmann方程，確定離子的濃度分布和射程等。Monte-Carlo（MC）模擬方法，它是建立在二體碰撞基礎(chǔ)之上的。分子動(dòng)力學(xué)（Molecular

Dynamics–MD)模擬方法。嚴(yán)格地求解

力學(xué)方程組，使用于低能碰撞過(guò)程。Magnetron

Sputtering

DepositionPlasma

Sputtering用于磁性隧道結(jié)的多靶濺射臺(tái)物理所Simulation

methodsSputtering

for

major

applications:

deposition

or

etchingDischarge

PlasmaEnergetic

ions

interaction

withed

atoms

sputtering

Sputtered

atoms

through

the

plasmaDepositionNumerical

methods

for

PlasmaFluid

modelsHybrid

modelsKinetic

modelsPIC

modelsDawson，Buneman，Hockney與Birdsall等學(xué)者于二十世紀(jì)五十年代中期起逐漸發(fā)展而來(lái)Deposition:

MC,

MDTransport

and

Deposition:

MCPIC

plus

direct

Monte

Carlo

approachPlasma,

neutral

gas,

and

surfacereactionsPlasma

Characteristics:

Fluid,

Hybrid,

PIC,

Solving

BoltzmannAt

low

pressure,

plasmas

do

not

follow

Maxwellian

distributionFas ectrons

tracked,

slow

electrons

and

ions,

fluid

modelErosion

profile

of

materials:

MC,

MD在幾個(gè)帕的氣壓范圍內(nèi)，由于電子和離子并不滿足熱平衡分布，流體假設(shè)也會(huì)存在問(wèn)題。Sputtering:

MC

MD混合模型:電子分為兩組，快電子和慢電子?？祀娮硬捎肕onte

Carlo方法被，慢電子和離子仍然以流體處理.通過(guò)對(duì)平面磁控濺射裝置進(jìn)行粒子模擬發(fā)現(xiàn)在鞘層區(qū)域電子滿足不是很好地滿足分布，而離子分布。Particle-in-cell/Monte

Carlo

collisions

treatment

of

an

Ar/O-2

magnetrondischarge

used

for

the

reactive

sputter

deposition

of

TiOx

fiThe

physical

processes

in

an

Ar/O-2

magnetron

discharge

used

for

the

reactivesputter

deposition

of

TiOx

thin

fi were

simulated

with

a

2d3v

particle-in-cell/Monte

Carlo

collisions

(PIC/MCC)

model.

The

plasma

species

taken

intoaccount

are

electrons,

Ar+

ions,

fast

Ar-f

atoms,

metastable

Ar-m*

atoms,

Ti+ions,

Ti

atoms,

O+

ions,

O-2(+)

ions,

O-

ions

and

O

atoms.

This

modelaccountsfor

plasma- interactions,

such

as

secondary

electron

emissionandsputtering,

and

the

effects

ofprocess

is

described

by

anpoisoning.

Furthermore,

the

depositionytical

surface

model.

The

influence

of

the

O-2/Argas

ratio

on

the

plasmapotential

and

on

the

species

densities

and

fluxes

isinvestigated.

Among

others,

it

is

shown

that

a

higher

O-2

pressure

causes

theregion

of

positive

plasma

potential

and

the

O-

density

to

be

more

spread,

and

thelatter

to

decrease.

On

the

other

hand,

the

deposition

rates

of

Ti

and

O

are

notmuch

affected

by

the

O-2/Ar

proportion.

Indeed,

the

predicted

stoichiometry

ofthe

deposited

TiOx

film

approaches

x

=

2

for

nearly

all

the

investigated

O-2/Arproportions.NEW

JPHYS.

11,

103010(2009)Sputter

deposition

of

MgxAlyOz

thin

fi inadual-magnetron

device:

a

multi-species

Monte

Carlo

modelA

multi-species

Monte

Carlo

(MC)

model,

combined

with

anytical

surface

model,

has

been

developed

in

order

to

investigatet eral

plasma

processes

occurring

during

the

sputter

depositionof

complex

oxide

fi in

a

dual-magnetron

sputter

deposition

system.The

important

plasma

species,

such

as

electrons,

Ar+

ions,

fast

Aratoms

and

sputtered

metal

atoms

(i.e.

Mg

and

Al

atoms)

are

describedwith

the

so-called

multi-species

MCmodel,

whereas

the

depositionofMgxAlyOz

fi is

treated

by

an ytical

surface

model.

With

thismodel,

we

are

able

to

describeall

important

plasma

species

aswell

asthe

deposition

process.

It

c so

be

used

to

predict

filmstoichiometries

of

complex

oxide

fi on

thesubstrate.M

Yusupov

etal

2012

New

J.

Phys.

14

073043Plasma-solid

interaction

in

fusion

devices邊緣等離子體和其周?chē)诘南嗷プ饔脤?duì)等離子體芯部產(chǎn)生重要的影邊響緣等離子體是熱絕緣層，同時(shí)控制雜質(zhì)進(jìn)入到等離子體芯部；壁受很強(qiáng)的熱負(fù)荷以及來(lái)自芯部粒子的轟擊，材料腐蝕及雜質(zhì)產(chǎn)生；氫的再循環(huán)過(guò)程的控制及對(duì)等離子體密度控制的影響；在熱和粒子作用下材料性能的穩(wěn)定及使用安全性/微觀結(jié)構(gòu)的變化中子輻照后材料活化及變性偏濾器主要功能有效地來(lái)自器壁的雜質(zhì)，減少對(duì)中心等離子體的污染。排出來(lái)自中心等離子體的粒子流和熱流。以及核聚變反應(yīng)過(guò)程中所產(chǎn)生的氦灰。偏濾器偏濾器是構(gòu)成高溫等離子與材料直接接觸的過(guò)渡區(qū)域：一面是溫度高達(dá)天文數(shù)字(幾億度)的等離子體,另一方面是通常的固體材料。Divertor

Is

a

Key

Component

of

Modern

Magnetic

Confinement

Systems偏濾器是現(xiàn)代磁約束核聚變裝置中至關(guān)重要的組成部分大部分來(lái)自于中心等離子體的熱流粒子流通過(guò)邊界層，Scrape-Off

Layer(SOL)，進(jìn)入偏濾器。等離子體轟擊導(dǎo)至偏濾器表面的損傷，熱負(fù)載，甚至破壞直接面對(duì)等離子體的部件。來(lái)自材料表面的中性粒子(原子,分子)以及雜質(zhì)反過(guò)來(lái)影響邊界以及中心等離子體的性能。此外，由等離子體與表面相互作用而產(chǎn)生的雜質(zhì)會(huì)與D，T

共同沉積(Redeposition)于等離子體輻照較弱的區(qū)域，導(dǎo)致核聚變反應(yīng)堆中氚的滯留(Tritium

Retention)問(wèn)題。偏濾器研究涉及到等離子體物理,原子物理以及表面物理等交叉領(lǐng)域SOLDivertorDivertor

Studies

Involve

Plasmas

Physics,

Atomic

Physics

and

Surface

PhysicsFeaturesFuture

operation

regime:ELMy

HmodeSteady

stateoperation:(Partial

deta

ent)Transient

events:(E ,Disruption)Normally,

less

than

300eV.However,the

heat

flux

is

huge.Energy

up

to 100MeVDeposit

power

up

toGW/m2Future

burning

plasmamachinesDeta

entASDEX

1983,

Stangeby,

book,

483Comparison

of

the

electron

temperatureand

pressure

profiles

‘upstream’

and

at

thedivertor

plate

for

three

valuesof

ne.(AlcatorC-Mod)calculatedmeasuredtt/

calculatedte

C(n

)2DOD

Degree

of

deta

entWhere

**

is

measured

flux

of

ions

tothe ,

measured

by

build-in

Langmuirprobes.JET

.

Measured

degree

of

deta ent,

DOD,

forthe

discharge

for

the

separatrix,

peak

andintegrated

ion

fluxes

for

both

the

inner

andtheouter

divertor,

versus

line-averaged

density.

Notethe

large

DOD

reached

at

the

inner

divertor,typical

of

total

divertor

deta

ent.JET.

Measured

and

extrapolated

ion

fluxes

to

theinner

and

outer

divertors

for

an

ohmic

densityramp.

The

same

quadratic

law

is

used

for

theseparatrix

ion

flux,

thepeak

ion

flux

to

thedivertor

and

theintegral

ion

flux

to

both

the

innerand

theouter

divertor.Features

of

Deta

entregions

does

decrease,

but

continues

toent

is low

temperatures,

Te

≈

a

feweVThe

detached

regime

where

nt

saturates

and

starts

to

fallDecrease

of

the

ion

saturation

current,

j+sat.Dα

radiation

from

theincrease

with

ne.A

further

feature

of

detaor

lessA

drop

of

plasma

pressure

along

the

SOL

is

another

key

characteristicof

divertor

deta

ent.A

change

in

the

ratio

of

certain

hydrogenic

emission

lines

from

thedivertor,

indicative

of

the

presence

of

volumebination.The

neutral

(D2)

pressure

in

regions

adjacent

to

the

divertor

leg

does

notdecrease

as

j+sat

falls,

but

continues

to

increase

just

as

the

Dα

emissiondoes.Deta

ent2143Z

Z

u

uc

L

n L

qA

useful

criterion

for

detaching,C

S

Pitcher

and

P

C

StangebyPlasma

Phys.

Control.

Fusion

39

(1997)

779–930(1)

increase

cZ

by

intentionally

addingLz:

Radiated

power

coefficientQu:‘upstream’

parallel

power

densityNu:

upstream

plasma

densityL:

connection

lengthimpurities;increase

LZ

by

using

impurities

withhigher

radiation

rates,

e.g.

using

neon

overcarbon;raise

the

upstream

density

nu;increase

the

connection

length

L;decrease

the

power

density

flowing

inthe

SOL

qu

by

increasing

the

mainplasmaradiation.MhD

InstabilityDestabilizing

forces

arise

basically

from:Current

gradientsPressure

gradients

+

adverse

MF

curvatureTwo

categories

of

the

resulting

instabilities:Ideal

modesResistive

modesBoth

instabilities

have

an

infinite

spectrum

of

posiible

modes,

each

beingcharacterized

byits

mode

numbers,

taking

a

form

expi(m-n),

m

andn

beingthe

poloidal

and

toroidal

mode

numbers.Scientific

WritingScientific

WritingInstabilities

relatedto

currentgradient:

曲模）Tearing

modes(

模）displacement

mode(位移模）Kink

instability at

low

beta(扭Instabilities

related

to

pressuregradient:Ballooning

modes

(氣球模）InternalKink

mode

(內(nèi) 模）displacement

mode

(

位移模）Disruptions(破裂）Scientific

WritingA

dramatic

event

inwhich

the

plasmaconfinement

issuddenly

destroyed.A

major

one:Damage

:

limit

therange

of

operation

incurrrentand

density;leads

to

large

mechanical

stressesand

to

intense

heat

loads復(fù)雜的非線性過(guò)程，磁流體不穩(wěn)定性或位移失控是起因,PWI是重要的后繼因素,等離子體的熱量和磁能迅速損失是

.破裂的四個(gè)階段預(yù)先兆階段(1

s)?:等離子體的小半徑收縮先兆階段（100

ms)：熱收縮發(fā)展為電流通道收縮。Thermal

quench(1

ms)：熱量很快損失Current

quench(10

ms)：放電很快終止。Scientific

Writing破裂不穩(wěn)定的共同特征：環(huán)向電流的突然熄滅；環(huán)向電壓示波信號(hào)出現(xiàn)負(fù)尖峰，但總電流不變；破裂過(guò)程中，X射線強(qiáng)度有較大的突然下降。Physics

of

disruptionsT eral

pattern

of

the

behaviourcan

bedescribed:The evolution

of

anunstable

current

profile

leading

tothegrowthof

a

tearing

mode, the

m=2modebeing

particularlyimportant.The nonlinear

growth

of

this

tearing

mode.A

sudden

relaxation

of

the

equilibrium

in

which

the

current

profileis

flattened

and

there

is

a

dramatic

loss

of

confinement

with

acollapse

of

the

plasmatemperature.The

total

current

decays.Under

some

circumstances

the

increased

toroidal

electrc

fieldassociated

with

the

increasedplasma produces

runawayelectrons.

These

electrons

can

carry

a

large

current

which

sometimespersists

after

the

plasma

current

decay

phase.Both

the

loss

of

plasma

energy

andthe

current

decayinduce

currentsin

the

vacuum

vessel

which

canproduce

very

large

forces

on

the

vessel.Scientific

WritingEdge

localized

modes

(E

)An

MHD

instability

occurring

in

the

edgeof

H-mode

plasmas

intoroidal

magnetic

fusion

experiments,

is

described.H-modeis

a

regimeof

enhanced

confinement

intoroidalmagnetic

fusion

devicesE lead

to

a

fast

(

ms)

loss

of

energy

and

particlesfrom

the

plasma

edge.E degrade

the

global

particle

and

energy

confinement

time.The

reduction

caused

by

ELM

transport

ismu ore

severe

for

theparticle

confinement

than

for

energy

confinement

time.Individual

E decrease

the

plasma

energy

and

particlecontent

by

roughly

5–10%.Scientific

WritingH

radiationpanying

each

ELMScientific

WritingType

IIIEachburst

continuousType

ISingle,

largerELM-free

Lead

to

impurity

accumulationScientific

WritingTypes

of

EType

I

Eare

essentially

gian

Ms.Large

heat

loss

pulse

involved,

a

threat.w

<

10

%Well

above

L-H

threshold,

>=20%low

frequency,

1-100HzFrequencyincreases

with

heating

power,

distinct

featureType

II

E are

intermediate

category,

avoiding

heat

pulse

ofType

I

but

not

leading

to

a

severe

loss

of

general

confinement.Triangularity

=(c+d)/2a.Type

IIIE are

continuous’

grassy”

Eassociate

with

a

substantial

deterioration

ofconfinement.Just

above

the

L-H

threthold,<=20%,

frequency,

1-1

kHz,

w<

1-5

%,