Data Analysis ToolsData Analysis Tools

Data Analysis ToolsData Analysis Tools• Higher level products and visualization

– Particle spectrograms in various coordinates.– Code also in class materials : idl/thm crib spectrograms proCode also in class materials : idl/thm_crib_spectrograms.pro

• DSL coordinates– Energy, theta/phi angle spectrograms– ;DSL coordinates– ; energy spectrogram– thm part getspec, probe=['b'], trange=['07-03-23/11:10','07-03-23/11:30'], $t _pa t_getspec, p obe [ b ], t a ge [ 0 03 3/ 0 , 0 03 3/ 30 ], $– data_type=['psif'],/energy, $– phi=[-135,-45], theta=[-45,45], erange=[25000,500000],suff='_dawn' – thm_part_getspec, probe=['b'], trange=['07-03-23/11:10','07-03-23/11:30'], $– data_type=['psif'],/energy, $– phi=[45,135], theta=[-45,45], erange=[25000,500000],suff='_dusk' – ; phi spectrogram– thm_part_getspec, probe=['b'], trange=['07-03-23/11:10','07-03-23/11:30'], $– data_type=['peir'],angle='phi', $– phi=[0,360], theta=[-90,90], erange=[1.5e4,2.5e4]– ; theta spectrogram

thm part getspec probe=['b'] trange=['07 03 23/11:10' '07 03 23/11:30'] $– thm_part_getspec, probe=[ b ], trange=[ 07-03-23/11:10 , 07-03-23/11:30 ], $– data_type=['peir'],angle='theta', $– phi=[0,360], theta=[-90,90], erange=[1.5e4,2.5e4]– tplot,'thb_fgs_gsm thb_psif_en_eflux_dusk thb_peir_an_eflux_*'– tlimit,['07-03-23/11:12','07-03-23/11:22']

1

Data Analysis Tools [2]• DSL coordinatesDSL coordinates

– Energy, theta/phi angle spectrograms– ;DSL coordinates (results)

2

Data Analysis ToolsData Analysis Tools• Higher level products and visualization

– Particle spectrograms in various coordinates• FAC coordinates (field aligned)• FAC coordinates (field aligned)

– Energy, pitch angle (pa) / gyro(velocity)phase angle spectrograms– ; Energy spectrogram– thm_part_getspec, probe=['b'], trange=['07-03-23/11:10','07-03-23/11:30'],$ – data_type=['psif'], /energy, $y gy– pitch=[0,45], suff='_para', $ – erange=[5000,25000],regrid=[32,16]– ; Gyro(velocity)phase spectrogram– thm_part_getspec, probe=['b'], trange=['07-03-23/11:10','07-03-23/11:30'],$ – data type=['psif'] angle='gyro' $– data_type=[ psif ], angle= gyro , $– pitch=[45,135], other_dim='ygsm', suff='_perp', $ – erange=[100000,150000],regrid=[32,16]– ; Pitch angle spectrogram– thm_part_getspec, probe=['b'], trange=['07-03-23/11:10','07-03-23/11:30'],$

$– data_type=['peer'], angle='pa', $– erange=[15000,25000],regrid=[32,16]– tplot,'thb_fgs_gsm thb_psif_en_eflux_para thb_psif_an_eflux_gyro_perp

thb_peer_an_eflux_pa'– tlimit,['07-03-23/11:12','07-03-23/11:22']tlimit,[ 07 03 23/11:12 , 07 03 23/11:22 ]

3

Data Analysis Tools• FAC coordinates (field aligned)FAC coordinates (field aligned)

– Energy, pitch angle (pa) / gyro(velocity)phase angle spectrograms (results)

4

Data Analysis Tools• Higher level products and visualization

– Particle spectrograms in various coordinates• FAC coordinates (field aligned) (Look in: thm_fac_matrix_make)

– other_dimension:» ; 'Xgse', (DEFAULT) translates from gse or gsm into FAC» ; Definition(works on GSE, or GSM): X Axis = on plane defined by Xgse - Z» ; Second coordinate definition: Y = Z x X gse» ; Second coordinate definition: Y = Z x X_gse» ; Third coordinate, X completes orthogonal RHS» ; 'Rgeo',translate from geo into FAC using radial position vector» ; Rgeo is radial position vector, positive radialy outwards.» ; Second coordinate definition: Y = Z x Rgeo (westward)» ; Third coordinate, X completes orthogonal RHS XYZ.» ; 'mRgeo' opposite to above» ; mRgeo , opposite to above » ; mRgeo is radial position vector, positive radially inwards.» ; 'Phigeo', translate into FAC using azimuthal position vector» ; Phigeo is the azimuthal geo position vector, positive Eastward» ; First coordinate definition: X = Phigeo x Z (positive outwards)» ; Second coordinate, Y ~ Phigeo (eastward) completes orthogonal RHS XYZ» ; 'mPhigeo' opposite to above» ; 'mPhigeo', opposite to above» ; Second coordinate, Y ~ mPhigeo (Westward) completes orthogonal RHS XYZ» ; 'Phism', translate into FAC using azimuthal Solar Magnetospheric vector.» ; Phism is "phi" vector of satellite position in SM coordinates.» ; Y Axis = on plane defined by Phism-Z, normal to Z» ; Second coordinate definition: X = Phism x Z; Third completes orthogonal RHS;

'mPhism' opposite to abo e; 'mPhism', opposite to above» ; mPhism is minus "phi" vector of satellite position in SM coordinates.» ; 'Ygsm', translate into FAC using cartesian Ygsm position as other dimension.» ; Y Axis on plane defined by Ygsm and Z» ; First coordinate definition: X = Ygsm x Z» ; Third completes orthogonal RHS XYZ

5

timespan,'7 6 8/08:00',16,/hourssc='c'

ESA penetrating radiation cleanupsdate='7 6 8/08:00'edate='7 6 8/24:00'thm_load_state,probe=sc,/get_suppthm_load_fit,probe=sc,data='fgs',coord='gsm',suff='_gsm'thm_load_fit,probe=sc,data='fgs',coord='dsl',suff='_dsl'thm_load_mom,probe=sc ; L2: onboard processed momsthm_load_esa,probe=sc ; L2: ground processed gmoms, omni spectrathm_load_sst,level=1,probe=sc;; CORRECT DENSITIES; load L0 omni spectra, all ESA data in memorythm_load_esa_pkt,probe=sc ;; PE?R MOMS/SPECTRA; Remove penetrating radiationtrange=[sdate,edate]calc," 'thc_peif_en_eflux_before'='thc_peif_en_eflux' "thm_part_moments, probe = sc, instrum = 'peif‘, $

t ffi ' t' $scpot_suffix = '_pxxm_pot', $trange=trange,erange=[0,31], $mag_suffix = '_fgs_dsl', tplotnames = tn, verbose = 2, $/bgnd_remove ;

calc," 'thc_peif_en_eflux_after'='thc_peif_en_eflux' ";trange=[sdate edate]trange=[sdate,edate]calc," 'thc_peer_en_eflux_before'='thc_peer_en_eflux' "thm_part_moments, probe = sc, instrum = 'peer', $

scpot_suffix = '_pxxm_pot', $trange=trange,erange=[0,31], $mag_suffix = '_fgs_dsl', tplotnames = tn, verbose = 2, $/bgnd remove ;

6

/bgnd_remove ;calc," 'thc_peer_en_eflux_after'='thc_peer_en_eflux' "store_data,'th'+sc+'_peer_en_eflux_pot',data= $'th'+sc+'_peer_en_eflux_after th'+sc+'_peer_sc_pot'

ylim,'th'+sc+'_pe??_en_eflux*',5,30000,1tplot,'th'+sc+'_fgs_gsm th'+sc+'_peif_en_eflux_* th'+sc+'_peer_en_eflux_*’

Example of Msheath/Mpause

ESS 261 Low Energy Particles7First limitation: s/c charging prevents cold ions from reaching sensor (2204-2207UT)Second limitation: s/c potential below lowest e- energy; cold electrons missed (2211-2214UT)

Example of Msheath/Mpause/Plumes

ESS 261 Low Energy Particles8

SST Products• Products: Full Reduced (Burst is same as full)• Products: Full, Reduced (Burst is same as full)

– Full: 16E x 64A– Reduced: 16E x 6A , orReduced: 16E x 6A , or

16E x 1A (omni)• Modes: Slow Survey, Fast Survey, Particle

Burst• Slow Survey:

– Full distributions (ions and electrons) at 5min resolution( )– Reduced, omnidirectional distributions: every spin

• Fast Survey:– Ions: Full distributions every spin– Electrons: Reduced distributions (16E x 6A) every spin

• Burst:– Ions: same as above– Electrons: Full distributions every spin

9

Data Analysis Tools• Pitfalls• Pitfalls

– Sun contamination• ; Sun contamination is masked on board but often fails

; Use keyword: mask_remove to removed masked bins and interpolate across y _ psectors

• ; Sun contamination is lefted unmasked recently (and most of the time) on board ; There is code to recognize the faulty bins (saturated) and remove them altogether.; This is called : method_sunpulse_clean='spin_fit' , or ‘median’ and tells the; programs to remove data beyond 2sigma away from spin-phase fit/median.

• ;Sun contamination/saturation also affects other channels due to electronic noise.;The code can remove the typical noise value and provide the remaining good; signal (assuming no saturation). The keyword is: enoise_bins and the; procedure is documented in: thm_crib_sst_contamination.pro

10

Sun contamination (thm_crib_sst_contamination.pro)– ;PROCEDURE: thm_crib_sst_contamination

;Purpose: 1 Demonstrate the basic procedure for removal of sun contamination– ;Purpose: 1. Demonstrate the basic procedure for removal of sun contamination,– ; electronic noise, and masking.– ; 2.. Demonstrate removal of suncontamination via various methods. – ; 3. Demonstrate the correction of inadvertant masking in SST data– ; 4. Demonstrate scaling data for loss of solid angle in SST measurements.– ; 5. Demonstrate substraction of electronic noise by selecting bins in a specific region– ; 6. Show how to use these techniques for both angular spectrograms,energy spectrgrams, and

moments.– ;SEE ALSO:– ; thm_sst_remove_sunpulse.pro(this routine has the majority of the documentation)– ; thm_part_moments.pro, thm_part_moments2.pro, thm_part_getspec.pro– ; thm_part_dist.pro, thm_sst_psif.pro, thm_sst_psef.pro,thm_sst_erange_bin_val.pro– ; thm_crib_part_getspec.pro

Sun contamination (sst_remove_sunpulse.pro)– ; Routine to perform a variety of calibrations on full distribution sst data These can; Routine to perform a variety of calibrations on full distribution sst data. These can

remove sun contamination and on-board masking. They can also scale the data to account for the loss of solid angle from the inability of the sst to measure directly along the probe geometric Z axis and the inability to measure directly along the probe geometric xy plane (ie X=0 Y=0 Z = n or X=n Y=m Z=0 are SST 'blind spots')

ESS 261 Energetic Particles11

geometric xy plane.(ie X 0,Y 0,Z n or X n,Y m,Z 0, are SST blind spots ) THM_REMOVE_SUNPULSE routine should not generally be called directly. Keywords to it will be passed down from higher level routines such as, thm_part_moments, thm_part_moments2, thm_part_dist,thm_part_getspec, thm_sst_psif, and thm_sst_psef

Data Analysis Tools• Pitfalls• Pitfalls

– Sun contamination– Read crib sheets:

thm crib sst contamination pro andthm_crib_sst_contamination.pro, anddocumented procedure: thm_sst_remove_sunpulse.pro

» ; » edit3dbins,thm_sst_psif(probe=sc, gettime(/c)), bins2mask» ; ON: Button1; OFF: Button2; QUIT: Button3» ; ON: Button1; OFF: Button2; QUIT: Button3» print,bins2mask» thm_part_getspec, probe=probe, trange=[sdate, edate], $» theta=[-45,0], phi=[0,360], $» data type=['psif'] start angle=0 $» data_type=[ psif ], start_angle=0,$»

angle='phi',method_sunpulse_clean='median',tplotsuffix='_ex2_t1',$» enoise_bins =

bins,enoise bgnd time=times,mask remove=.99bins,enoise_bgnd_time times,mask_remove .99» tplot

12

Ground processing (particles only)• Pitfalls• Pitfalls

– Sun contamination: Bin selection » ;

13

Density CorrectionInterpolate densities• Interpolate densities

• Add• date='2008-03-01'• startdate = '2008-03-01/00:00'• timespan,startdate, 4.0, /hour• Trange=['08-03-01/00:00','08-03-01/04:00']

T ['08 03 01/01 40' '08 03 01/02 40']• Tzoom=['08-03-01/01:40','08-03-01/02:40']

• ;... select exact time interval to calculate join ESA/SST moments• tbeg = time_double(date+'/00:00')• tend = time_double(date+'/04:00')• ;select a probe• sc='b'• thm_load_state,probe=sc,coord='gsm',/get_support

h l d fi l l 1 b• thm_load_fit, level=1, probe=sc,datatype=['efs', 'fgs'],/verbose

• thm_cotrans,strjoin('th'+sc+'_fgs'),out_suf='_gsm', in_c='dsl', out_c='gsm'

• ;• ; SST now• thm_load_sst,probe=sc,lev=1• thm_part_moments, probe = sc, instr= ['ps?f'], $

$

Ni

• moments = ['density', 'velocity', 't3'], $• mag_suffix='_peir_magt3', $• scpot_suffix='_peir_sc_pot';,/median• ; work in gsm• thm_cotrans,'th'+sc+'_ps?f_velocity',

in_coord='dsl',out_coord='gsm',out_suffix='_gsm'• ;• ; ESA now

Ne

• thm_load_esa,probe=sc• ; Interpolate densities• tinterpol_mxn,'th'+sc+'_peer_density',

'th'+sc+'_peir_density',/overwrite,/nan_extrapolate• tinterpol_mxn,'th'+sc+'_ps?f_density',

'th'+sc+'_peir_density',/overwrite,/nan_extrapolate• …• ; ...total ion density• totNi = sst_i_n.y + esa_i_n.y

14

Velocity CorrectionI t l t d iti• Interpolate densities

• Add flux• ;• ;

l• ; ...sst Flux• sstFi = sst_i_v.y*0.• sstFi[*,0] = sst_i_n.y*sst_i_v.y[*,0]• sstFi[*,1] = sst_i_n.y*sst_i_v.y[*,1]• sstFi[*,2] = sst_i_n.y*sst_i_v.y[*,2]

• ; ...esa Flux; ...esa Flux• esaFi = esa_i_v.y*0.• esaFi[*,0] = esa_i_n.y*esa_i_v.y[*,0]• esaFi[*,1] = esa_i_n.y*esa_i_v.y[*,1]• esaFi[*,2] = esa_i_n.y*esa_i_v.y[*,2]

• ; ...total ion density• totNi = sst_i_n.y + esa_i_n.y

• store_data, 'th'+sc+'_Ni',$data={x:esa_i_n.x, y:totNi}

• options, 'th'+sc+'_Ni', 'ytitle', $'Ni !C!C1/cm!U3'

• ylim 'th'+sc+' Ni' 0 01 1 1• ylim, th +sc+ _Ni , 0.01, 1., 1

• ; ...total ion velocity (GSM)• totVi = esa_i_v.y*0.• totVi[*,0] = (sstFi[*,0]+esaFi[*,0])/totNi• totVi[*,1] = (sstFi[*,1]+esaFi[*,1])/totNi• totVi[*,2] = (sstFi[*,2]+esaFi[*,2])/totNi

15

Pressure CorrectionRemove SST noise• Remove SST noise

• Interpolate pressures• Then add• ;• ; SST now• ; SST now• thm_load_sst,probe=sc,lev=1• thm_part_moments, probe = sc, instr= ['ps?f'], $• moments = ['density', 'velocity', 't3'], $• mag_suffix='_peir_magt3', $• scpot_suffix='_peir_sc_pot';,/median• ; …interpolate• ; … add• ; ...pressure• ; ...SST: perpendicular temperature only• sst_Tperp = .5*(sst_i_t3.y[*,0]+sst_i_t3.y[*,1])• sst_i_p_nPa = 0.16*.001*sst_i_n.y * sst_Tperp • ; perp. pressure in nPa• store_data, 'th'+sc+'_psif_p_perp_nPa', $• data={x:sst_i_n.x, y:sst_i_p_nPa}• options, 'th'+sc+' psif p perp nPa', $p _p _p_p p_• 'ytitle', 'sst Pi !C!CnPa'

• ; ...ESA: scalar temperature• esa_Ti = total(esa_i_T.y,2)/3.• store_data,'Ti_th'+sc+'_peir', $• data={x:esa_i_n.x, y:esa_Ti}• ; ...ESA ion pressure:• esa i p nPa = 0.16 *.001 * esa i n.y*esa Ti_ _p_ _ _ y _• ; scalar pressure in nPa• store_data, 'th'+sc+'_peir_p_nPa', $• data={x:esa_i_n.x, y:esa_i_p_nPa}• options, 'th'+sc+'_peir_p_nPa', $• 'ytitle', 'esa Pi !C!CnPa'

• ; ...Total ion pressure• totPi = sst i p nPa + esa i p nPa_ _p_ _ _p_• store_data, 'th'+sc+'_i_p_nPa', $• data={x:esa_i_n.x, y:totPi}• options, 'th'+sc+'_i_p_nPa', 'ytitle', 'Pi !C!CnPa'

16

Finite gyroradius techniquesI G di l d t t h i• Ion Gyroradius large compared to magnetospheric boundaries– Can be used to remotely sense speed

To Tail

and thickness of boundaries– Assumption is that boundary is sharp

and flux has step function across• Application at the magnetopause

THEMIS• Application at the magnetopause• Application at the magnetotail

– Can also be applied to waves ifparticle gradient is sufficiently high

• Application on ULF waves atinner magnetosphere

To Earth

Method exploits finite iongyroradius to remotely sense

To EarthTo Sun

gyroradius to remotely senseapproaching ion boundary andmeasure boundary speed (V )17

At the magnetotail325kmi,thermal-tail (4keV,20nT)= ~325km

i,super-thermal (50keV,20nT)= ~2200km

Plasma Sheet Thickness ~ 1-3 REBoundary Layer Thickness 500 2000kmBoundary Layer Thickness ~500-2000kmCurrent layer Thickness ~ 500-2000km

Waves Across Boundary: ~1000-10,000kmAlong Boundary: Normal : 1 10Along Boundary: ~Normal : 1-10

RE

For magnetotail particles, the current layer andFor magnetotail particles, the current layer and plasma sheet boundary layer are sharp compared to the superthermal ion gyroradius and the magnetic field is the same direction in the plasma sheet and outside (the lobe). Thisthe plasma sheet and outside (the lobe). This means we can use the measured field to determine gyrocenters both at the outer plasma sheet and the lobe, on either side of the hot magnetotail boundary.magnetotail boundary.

18

Sid Vi ( l ti ) 52oSide View (elevations)

SpinSST:El ti

25o

52

SpinAxis

Elevationdirection(DSL) 25o

To Sun( DSL) -25o

-52o

ESA:Elevation 11 25o

33.75o

Elevationdirection(DSL)

11.25o

19

Top View (sectors)p ( )For ESA and SST (0=Sun)

Spin axisp

11.25o

33 75

To Sun (0o)

Spin motiondirection ( DSL)

33.75o

Normal to Sun +90oNormal to Sun, +90o

20

TH-BTH-B

(a)

(b)

(a)

(b)

B fielda im th You care to time this!

(c)(c)

Particle motion direction

azimuth(solid white)

You care to time this!(+/- 90o to Bfield azimuth)

(d)

(e)

(d)

(e)

Particle motion directionCoordinate: ( DSL)Energy: 125-175keV

( )( )

Note: direction dependson spin axis. -B field

i thazimuth(dashed white)

21

Multiple spacecraft, energies, elevations

A

B

D….

E

Elev: 25deg E=30-50keVElev: 25deg, E=80-120keV

22

Vi_const 310km/sec/keV fci_cons 0.0152Hz/nT B 30nTTi 40keV rho_ion 683kmTi 100keV rho_ion 1081km Ti 150keV rho_ion 1323km Ti 300keV rho_ion 1872km

SC E (keV) detector d(deg) r timeB 40 SPW -128.0 683.4 11:19:29B 40 SPE -52.0 683.4 11:19:39B 40 SEW -155.0 683.4 11:19:18B 40 SEE -25.0 683.4 11:19:42B 40 NPW 128 0 683 4 11:19:29

Note:NEE= North-Equatorial, EastNPW=North-Equatorial, WestAngles measured from East directionB 40 NPW 128.0 683.4 11:19:29

B 40 NPE 52.0 683.4 11:19:38B 40 NEW 155.0 683.4 11:19:24B 40 NEE 25.0 683.4 11:19:43B 100 SPW -128.0 1080.5 11:19:17B 100 SPE -52.0 1080.5 11:19:42B 100 SEW -155.0 1080.5 11:19:20

Angles measured from East direction-25deg elevation, 90deg East = SEE+52deg elevation, 90deg East = NPE… Spin axis

B 100 SEE -25.0 1080.5 11:19:45B 100 NPW 128.0 1080.5 11:19:20B 100 NPE 52.0 1080.5 11:19:45B 100 NEW 155.0 1080.5 11:19:23B 100 NEE 25.0 1080.5 11:19:48B 150 SPW -128.0 1323.4 11:19:10B 150 SPE 52 0 1323 4 11:19:44

pNPW

NEWNPE

NEEB 150 SPE -52.0 1323.4 11:19:44B 150 SEW -155.0 1323.4 11:19:14B 150 SEE -25.0 1323.4 11:19:51B 150 NPW 128.0 1323.4 11:19:23B 150 NPE 52.0 1323.4 11:19:45B 150 NEW 155.0 1323.4 11:19:13B 150 NEE 25.0 1323.4 11:19:48

B

SEW SEEB 300 SPW -128.0 1871.5 11:19:10B 300 SPE -52.0 1871.5 11:19:44B 300 SEW -155.0 1871.5 11:19:14B 300 SEE -25.0 1871.5 11:19:51B 300 NPW 128.0 1871.5 11:19:23B 300 NPE 52.0 1871.5 11:19:45B 300 NEW 155 0 1871 5 11 19 13

SEW

SPW

SEE

SPEB 300 NEW 155.0 1871.5 11:19:13B 300 NEE 25.0 1871.5 11:19:48 Boundary

23

Spin axis

BNPW

NEW

NPE

NEEV: NEE Particle direction

NEW NEE

YSC

SEW

SPW

SEE

SPEZ

d

SPW SPE

Boundary n

Cold/tenuousY

GCNEE

Hot/dense

Show: d=*sin(-)Note: d negative if moving towards spacecraftNote: d negative if moving towards spacecraft

24

P d• Procedure– For a given , determine variance of data for all – Find minimum in variance, this determines (boundary direction)– Distance as function of time determines boundary speed

– intro_ascii,'remote_sense_A.txt',delta,rho,hh,mm,ss,nskip=13,format="(25x,f6.1,f8.1,3(1x,i2))"– ;– angle=fltarr(73)– chisqrd=fltarr(73)– for ijk=0,72 do begin

il fl t(ijk*5)– epsilon=float(ijk*5)– get_d_vs_dt,epsilon,hh,mm,ss,rho,delta,dist,times– yfit=dist & yfit(*)=0.– chi2=dist & chi2(*)=0.– coeffs=svdfit(times,dist,2,yfit=yfit,chisq=chi2)– angle(ijk)=epsilon– chisqrd(ijk)=chi2chisqrd(ijk) chi2– endfor– ipos=indgen(30)+43– chisqrd_min=min(chisqrd(ipos),imin)– plot,angle,chisqrd– print,angle(ipos(imin)),chisqrd(ipos(imin))– ;– stop

25

ZDP d

Y

D

BA

• Procedure– Note two minima (identical solutions)

• One for approaching boundary at V>0• One for receding boundary at V<0

– Convention that d<0 if boundary

1000

km V ~ 70km/sAConvention that d<0 if boundary

moves towards spacecraftallows us to pick one of the two(positive slope of d versus time)

= 280o= 280o

Var

ianc

e,

2V

aria

nce,

2

V

Boundary orientation,

V

Boundary orientation,

26

Probe: TH-BAngle to Y east=280degm

)

Probe: TH-BAngle to Y east=280degm

) Angle to Y_east 280degD0 = -2224 kmV0 = 69.9 km/stcross= 11:19:31.81

dista

nce

(km Angle to Y_east 280deg

D0 = -2224 kmV0 = 69.9 km/stcross= 11:19:31.81

dista

nce

(km

Bou

ndar

y d

Bou

ndar

y d

Time since 11:19:00Time since 11:19:00

tcross V [km/s] [deg]

D 11:19:27.6 75 270

B 11:19:31.8 70 280

A 11:19:38.4 80 275

Table 1. Results of remote sensing analysis on the inner probes

Timing of the arrivals of the other signatures at the inner three spacecraft (From Angelopoulos et al. 2008First Results from the THEMIS mission)

27

At the magnetopause = 200kmi,sheath (0.5keV,10nT)= ~200kmi,m-sphere (10keV,10nT)= ~1000km

Magnetopause Thickness ~ 6000kmCurrent layer Thickness ~ 500km

FTE scale, Normal To Boundary: ~6000kmAlong Boundary: ~ 1-3 RE across

For leaking magnetospheric particles, the currentlayer is sharp compared to the ion gyroradius andthe magnetic field is the same direction in the sheath and the magnetopause outside the current layer. This means we can use the measured field outside themeans we can use the measured field outside themagnetopause to determine gyrocenters both at the magnetopause and the magnetosheath on either side of the hot magnetopause boundary.

28

YgseYgse

Magnetopause encounter on July 12, 2007

C

DTH-B AE

Ygse

C

DTH-B AE

Ygse

(a)(b)(a)(b)

XgseXgse

(c)(c)

XgseXgse

(d)(d)

(e)

(f)

(e)

(f)

Magnetic field angle is 60deg below spin plane and +120deg in azimuth i.e., anti-Sunward and roughly tangent to the magnetopause. The particle velocities, centered at 52deg above the

(g)(h)(g)(h)

spin plane, have roughly 90o pitch angles, with gyro-centers that were on the Earthward side of the spacecraft. The energy spectra of the NP particles show clearly the arrival of the FTE ahead of its magnetic signature, remotely sensing its arri al d e to the finite g roradi s (h)(h)sensing its arrival due to the finite gyroradius effect of the energetic particles. T=55s, i,100keV, 28nT) =1150km, V=40km/s

At the near-Earth magnetosphere

30

At the near-Earth magnetosphereRemote sensing of wavesgin ESA data, at the mostappropriate coordinateSystem, I.e, field alignedcoordinates

timespan,'7 11 07/10',2,/hours & sc='a'

coordinates. gyro=0o => Earthward particles

thm_load_state,probe=sc,/get_supp

thm_load_fit,probe=sc,data='fgs',coord='gsm',suff='_gsm'

thm_load_mom,probe=sc ; L2: onboard processed moms

thm_load_esa,probe=sc ; L2: gmoms, omni spectra

tplot 'tha fgs gsm tha pxxm pot tha pe?m densitytplot,'tha_fgs_gsm tha_pxxm_pot tha_pe?m_density tha_pe?r_en_eflux'

;

trange=['07-11-07/11:00','07-11-07/11:30']

thm_part_getspec, probe=['a'], trange=trange, angle='gyro', $$

pitch=[45,135], other_dim='mPhism', $

; /normalize, $

data_type=['peir'], regrid=[32,16]

tplot,'tha peir an eflux gyro tha fgs gsm tha pxxm pottplot, tha_peir_an_eflux_gyro tha_fgs_gsm tha_pxxm_pot tha_pe?m_density tha_pe?r_en_eflux'

Korotova et al., 2009