Inner Magnetosphere`s effects on Radiation Belt
Transcript of 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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(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$ects
on ra!ial transport o) ra!iation elt electrons/
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Motivation: *a!iation BeltsMotivation: *a!iation Belts
iscovery o) 1an Allen ra!iationelts '3plorer , 568
+rappe! protons 7 electrons,
spatial !istrition 29 *';,
ener%y
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ynamical *a!iation Beltynamical *a!iation Belt
'lectrons'lectrons
=hy st!y ra!iation
elt electrons>
Becase they are
physically interestin%
*a!iation !ama%e to
spacecra)t an! hman
activity in space
(oal: !escrie an!pre!ict ho& ra!iation
elts evolves in time at
a %iven point in spaceGreen [2002]
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Solar =in! an! Ma%netosphereSolar =in! an! Ma%netosphere
Avera%e pictre o) solar &in! an! ma%netosphere ma%netic -el!,
re%ions, inner ma%/ plasmas;
1ariations o) ?s&, IM@ B cases ma%netospheric !ynamics
Ring Current
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Ma%netic StormsMa%netic Storms Most intense solar
&in!9ma%netospherecoplin%
IM@ B soth&ar!,
stron% electric -el! in
the tail
@ormation o) rin%
crrent an! its e$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
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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