Inner Magnetosphere`s effects on Radiation Belt

8/17/2019 Inner Magnetosphere`s effects on Radiation Belt

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ruc ure an ynam cs o nner

MagnetosphereMagnetosphere

and Their Eects on Radiation Beltand Their Eects on Radiation Belt

ElectronsElectrons

Chia-Lin uang Boston University, MA, USA

CISM Seminar, March 24th, 2008

Special thanks: Harlan Spence, Mary H!son, "ohn #yon, "e$ H%hes, Ho&ar! Sin%er, Scot 'lkin%ton, an! many more

APL


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2

(oals o) my *esearch(oals o) my *esearch

+o n!erstan! the physics !escriin% the strctre an!!ynamics o) -el! con-%rations in the inner

ma%netosphere

+o assess the per)ormance o) %loal ma%netospheric

mo!els n!er varios con!itions

+o .anti)y the response o) %loal ma%netic an! electric

-el!s to solar &in! variations, an! ltimately their e$ects

on ra!ial transport o) ra!iation elt electrons/


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3

Motivation: *a!iation BeltsMotivation: *a!iation Belts

iscovery o) 1an Allen ra!iationelts '3plorer , 568

+rappe! protons 7 electrons,

spatial !istrition 29 *';,

ener%y


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4

ynamical *a!iation Beltynamical *a!iation Belt

'lectrons'lectrons

=hy st!y ra!iation

elt electrons>

Becase they are

physically interestin%

*a!iation !ama%e to

spacecra)t an! hman

activity in space

(oal: !escrie an!pre!ict ho& ra!iation

elts evolves in time at

a %iven point in spaceGreen [2002]


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5

Solar =in! an! Ma%netosphereSolar =in! an! Ma%netosphere

Avera%e pictre o) solar &in! an! ma%netosphere ma%netic -el!,

re%ions, inner ma%/ plasmas;

1ariations o) ?s&, IM@ B cases ma%netospheric !ynamics

Ring Current


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6

Ma%netic StormsMa%netic Storms Most intense solar

&in!9ma%netospherecoplin%

IM@ B soth&ar!,

stron% electric -el! in

the tail

@ormation o) rin%

crrent an! its e$ect to-el! con-%rations

st measres rin% crrent !evelopment

Storm s!!en commencement SSC;,main phase, an! recovery phase

ration: !ays


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Ma%netospheric ?lsationsMa%netospheric ?lsations

Ultra9lo&9)re.ency U#@; MH &aves @re.ency an! time scale: 29 mH, 90 mintes

@iel! ctation ma%nit!e

@irst oserve! in 5th centry

=aves stan!in% alon% the ma%netic -el! lines connect toionospheres Dungey , 564D

Morpholo%y an! %eneration mechanisms are not )lly

n!erstoo!


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(loal Ma%netospheric Mo!els(loal Ma%netospheric Mo!els ?rovi!e %loal B an! ' -el!s nee!e! )or ra!iation elt st!y

ata9ase!: +sy%anenko mo!els ?arameterie!, .ansi9static state o) avera%e ma%netic -el!

con-%rations

?hysics9ase!: (loal MH co!e

Sel)9consistent, time !epen!ent, realistic ma%netosphere

Importance an! applications, vali!ation o) the %loal mo!els

' m p i r i c

a l m o ! e l

( l o , a l M H 0 s i m l a t i o n

#@M MH co!e +sy%anenko mo!el


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Char%e! ?article Motion inChar%e! ?article Motion in

Ma%netosphereMa%netosphere (yro, once an! !ri)t motions

(yro


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=hy is it so Har!> =hat =ol!=hy is it so Har!> =hat =ol!

Help>Help>

?ropose! physical processes !cceleration: lar%e9 an! small9scale recirclations, heatin% y

=histler &aves, ra!ial !i$sion y U#@ &aves, csp sorce,sstorm inEection, s!!en implse o) solar &in! pressre an!etc/

Loss: pitch an%le !i$sion, Colom collision, an!Ma%netopase sha!o&in%/

Transport

iFclties to !i$erentiate the mechanisms:

#ack o) Measrements #ack o) an accrate ma%netic an! electric -el! mo!el

Convertin% particle 3 to !istrition )nction is tricky

Gee! etter n!erstan!in% o) &ave9particle interactions

Comptational resorce


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+he *est o) the +alk +he *est o) the +alk

Ma%netospheric -el! !ynamics: !ata 7 mo!els #ar%e9scale: Ma%netic storms

Small9scale: U#@ &ave -el!s

'$ects o) -el! !ynamics on ra!iation eltelectrons

Create &ave -el! simlations

anti)y electron ra!ial transport in the &ave -el!s


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#yon9@e!!er9Moary Co!e#yon9@e!!er9Moary Co!e #yon et al/2004D

Uses the i!eal MH e.ations to mo!el the interactionet&een the solar &in!, ma%netosphere, an! ionosphere

Simlation !omain an! %ri!

2 electrostatic ionosphere

Solar &in! inpts

@iel! con-%rations an!

&ave -el! vali!ations y

comparin% & (J'S !ata

LFM grid in equatorial plane


13/3913

ataMo!el Case St!yataMo!el Case St!y

2492K Septemer 558 maEor storm event st minimm 92L n+;

#@M inpts: solar &in! an! IM@ !ata

(eosynchronos orit

Sep98 event: solar wind data and Dst

Compare #@M an! (J'S B9-el!at ('J orit


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Statistical ataMo!elStatistical ataMo!el

ComparisonsComparisons

5 ma%netic storms 29month non9storm

interval

#@M -el! lines are

consistently n!er9

stretche!, especially!rin% storm9time, on

the ni%htsi!e

?re!ict reasonale

non9storm time -el!

Improvements o) #@M

Increase %ri!

resoltion

A!! rin% crrent

Field residual B = BMHD – B!"S


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a s ca compar son o +sy%anenko mo!els an! (J'S +sy%anenko mo!els an! (J'S

!ata!ata 62 maEor ma%netic storm )rom 55K to 2004

+S06 has the est per)ormance in all local time an! storm levels

#nder$esti%ate

&er'e(t predi(tion

!ver$esti%ate

Field residual B = B!"S – B)%odel

)9* )+, )S+-

) - l! ! lC ) - l! ! l


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Conse.ence o) -el! mo!elConse.ence o) -el! mo!el

errorserrors Inaccrate B9-el! mo!el col! alter the reslts o) relate! st!ies

'3ample: ra!ial pro-les o) phase space !ensity o) ra!iation elt electrons

iscrepancies et&een +sy%anenko mo!els sin% same inpts

Mo!el -el! lines trace! )rom (J'S98Ns position le)t;

?itch an%les at (J'S98Ns position an! at ma%netic e.ator ri%ht;

~15% errorbetween T96

and TS05

U#@ =


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U#@ =aves naves nMa%netosphereMa%netosphere

=ave sorces: shear o&, variation in the solar &in! pressre, IM@ B, an!instaility etc/

?revios st!ies: inte%rate! &ave po&er, &ave occrrence

Ge3t, calclate &ave po&er as )nction o) )re.ency sin% (J'S !ata

&ave -el! pre!iction o) #@M an! + mo!el/

NASA


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?o&er Spectral ensity ?S;?o&er Spectral ensity ?S;

Calclate ?S sin% L9

hor (J'S B9-el! !ata

?roce!res:

/ +ake ot s!!en -el!

chan%e

2/ e9tren! &

polynomial -t

L/ e9spike & L stan!ar!

!eviations

4/ Hi%h pass -lter 0/6mH;

6/ @@+ to otain ?S

n+2HD


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(J'S B9-el! ?Ss in @AC(J'S B9-el! ?Ss in @AC

5 years o) (J'S !ata (98, (95 an! (90satellites;

@iel!9ali%ne! coor!inates

Separate into L9hor intervals 8 local time sectors;

Calclate ?Ss

Me!ian ?S in each )re.ency in

"oon

Midnight

Da#nDus$

Co%pressional ./i%ut0al Radial


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Sortin% (J'S BSortin% (J'S B ?S y S= 13?S y S= 13

? S 0

B C n + 2 I H A D


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Sortin% (J'S BSortin% (J'S B ?S y IM@ B?S y IM@ B

? S 0

B C n + 2 I H A D

! " o # t $ w

a r d

! n o r t $ w a r d


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U#@ =aves in #@M co!eU#@ =aves in #@M co!eirect comparisons o) U#@ &aves !rin% @e9Apr 55K in -el!9

ali%ne! coor!/

? S 0

B C n + 2 I H A D

Lo(al )i%e

L F M o u

t p u t

! " S d a t a

B1 o&'re""(ona)

Bn

rad(a)

B2

a!(t$a)

*#$

better t$ane+'eted,


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st an! Op e$ects on U#@ &avest an! Op e$ects on U#@ &ave

po&erpo&er

Hig0 3p interval

-' . 4

Low 3p interval-' / 4

Hig0 Dst interval Low Dst interval

"t 40 nT "t 40 nT

U#@ &ave po&er

has hi%her

!epen!ence on Op

than st

'ven tho%h #@M

!oes not

repro!ce per)ect

rin% crrent, it

pre!ictsreasonale -el!

pertrations

U#@ &ave pre!iction o) +sy%anenkoU#@ &ave pre!iction o) +sy%anenko


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U#@ &ave pre!iction o) +sy%anenkoU#@ &ave pre!iction o) +sy%anenko

mo!elmo!el

) S + - % o d e l

L F M ( o d e

! " S d a t a

Un!erestimates

the &ave po&er

at

%eosynchronos

orit

@iel! ctations

are reslts o) an

e3ternal !river

#ack o) the

internal physical

processes


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Smmary o) Mo!elSmmary o) Mo!el

?er)ormance?er)ormance

Use #@MNs &ave -el!s !rin% non9storm time to st!y U#@

&ave e$ects on ra!iation elt electrons

Sch con!itions e3ist !rin% hi%h spee! solar &in!

streams intervals/

U#@ = '$ t *BU#@ =ave '$ects on *B


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U#@ =ave '$ects on *BU#@ =ave '$ects on *B

'lectrons'lectrons Stron% correlation et&een U#@ &ave po&er an! ra!iation

elt electron 3 Rostoker et al., 558D

ri)t resonant theory Hudson et al., 555 an! Elkington et al., 555D

U#@ &aves can e$ectively accelerate relativistic electrons

antitative !escription o) &ave9particle interaction

o"toer et a) [1998]

)(nton et a) [2003]

? i l i$ i i? ti l i$ i i


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?article i$sion in?article i$sion in

Ma%netosphereMa%netosphere

Diusion theory% timeevoltion o) a !istrition

o) particles &hose

traEectories are !istre!

y innmerale small,

ran!om chan%es/

?itch an%le !i$sion loss;:

violate st or 2n! invariant

*a!ial !i$sion transport

an! acceleration;: violate

Lr! invariant

( )

∂

∂

∂

∂=

∂

∂ f L

L L D

Lt

f LL

2

2

1[ ]1

2

2

−∆

= day L

D LLτ

ad(a) d(::#"(on oe::((ent;ad(a) d(::#"(on e


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*a!ial i$sion CoeFcient,*a!ial i$sion CoeFcient,

####

#ar%e !eviations in previosst!ies

?ossile shortcomin%s

Jver simpli-e! theoretical

assmptions

#ack o) accrate ma%netic -el!

mo!el an! &ave -el! map

InsFcient measrement

M/ =altNs s%%estion: )ollo& *B

particles in realistic

ma%netospheric con-%rations

=alt 554D

E&perimental 'solid( and

theoretical 'dashed( DLL )alues

=hen oes #@M ?re!ict =aves=hen oes #@M ?re!ict =aves


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=hen oes #@M ?re!ict =aves=hen oes #@M ?re!ict =aves

=ell>=ell>

(J'S an! #@M ?Sssorte! y solar &in!

13 ins

#@M !oes etter !rin%

mo!erate activities

Create U#@ &ave

activities y !rivin%

the #@M co!e &ith

synthetic solar &in!

pressre inpt

4 !

! !

o ar = n ?ressreo ar n ressre


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o ar = n ?ressreo ar n ressre1ariation1ariation

Histo%rams o) solar &in! !ynamic

pressre )rom 5 years o) =in! !ata )or13 P *++, ,++, an! ++ kms ins

Make time9series pressre variations

proportional to solar &in! 13

Synthetic Solar =in! ?ressreSynthetic Solar =in! ?ressre


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Synthetic Solar =in! ?ressreSynthetic Solar =in! ?ressre13;13;

#@M inpts: Constant 13 variation in nmer !ensity/

Gorth&ar! IM@ B Q2 n+;, to isolate pressre !riven &aves/

I!ealie! #@M 13 simlations sin% hi%h time an! spatial resoltions


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I!ealie! 13 SimlationsI!ealie! 13 Simlations

(J'S statisticalst!y 5 years!ata; as )nctiono) 13 Rmostlynorth&ar! IM@;

rive #@M topro!ce Rreal U#@&aves &ith solar&in! !ynamicpressre variationsas )nction o) 13Rprelynorth&ar! IM@; #

@ M

1 3

r n s

( J ' S ! a t a

.& / *++ .& / ,++ .&/++

' = ? S ti l' =a e ?o er Spatial


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'T =ave ?o&er Spatial'T =ave ?o&er Spatial

istritionsistritions

=ave po&er increases as 13 ?! variations; increases

=ave amplit!e is hi%her at lar%er ra!ial !istance &ave sorce;

])/[()( 2

6

5.0

mmV df f PSD power Wave

mHz

mHz

E

∫ =

ϕ


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*a!iation Belt Simlations*a!iation Belt Simlations

Test particle code 'lkin%ton et al/, 2004D

Satis)y st a!iaatic invariant (i!in% center appro3imation

50o pitch an%le electron

?sh particles sin% #@M ma%netic an! electric-el!s

Simlate particles in

#@M 13 P 400 an! K00 kms rns

?article initial con!itions

@i3e! P 800 Me1(

*a!ial: 4 to 8 *'

o aimthal !irection


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*ate o) 'lectron *a!ial +ransport*ate o) 'lectron *a!ial +ransport####;;

Convert particle location to #V Roederer , 50D

Calclate or ra!ial !i$sion coeFcient, ##13; τ 2

2 L D LL

∆=

DLL in(reases wit0 L

DLL

in(reases

wit0 56

Φ

−=

E R

k L

0* 2π

CC l1 l I


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Compare Compare #### 1ales I1ales I

+he maEor !i$erences

et&een previosst!ies an! this &ork

Amplit!e o) &ave -el!

IM@ B

Ma%netic -el! mo!el

?article ener%y Calclatin% metho!

+heoretical assmption

i$erences make it

impossile )or a )air

comparison

Hi%hli%ht: Selesnick et al. 55D

∆ ~10 nT

∆ ~1 nT

∆ ~2 nT


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Compare Compare #### 1ales II1ales II

## < !B

2

Schulz and Lanzerotti, 54D

A)ter scalin% )or &ave po&er

Compare to Selesnick et al.

55D a%ain

Match &ell &ith 13PK00 kms

interval #9!epen!ent;

Avera%e 13 o) Selesnick et al.

200D an! IM@ B e$ect

+his s%%ests that ra!ial

!i$sion is &ell9simlate!, can

!i$erentiate )rom other physical

processes

##13, B, ∆?!yn, Op etc/;


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SmmarySmmary

+S06 est pre!icts ('J ma%netic -el!s in all con!itions

#@M has %oo! pre!ictions o) .iet time -el!s, t not )orstorm time

U#@ &ave strctres an! amplit!es at ('J sorte! yselecte! parameters

U#@ &ave -el! pre!ictions: #@M is very %oo!, t not +S06

*a!ial !i$sion coeFcient !erive! )rom MH?article co!e


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Conclsions an! AchievementsConclsions an! Achievements

Most comprehensive, in!epen!ent st!y o) state9o)9the9artempirical ma%netic -el! mo!els

Most .antitative investi%ation o) %loal MH simlations inthe inner ma%netosphere

Most comprehensive oservational U#@ &ave -el!s at%eosynchronos orit !e!icate! to oter one electronst!y

@irst e3ploration on U#@ &ave -el! per)ormance o) %loalma%netospheric mo!els

@irst ## calclation y )ollo&in% relativistic electrons in

realistic, sel)9consistent -el! con-%rations an! &ave -el!so) an MH co!e

Inner Magnetosphere`s effects on Radiation Belt

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