TTwo-dimensional wo-dimensional CCross-phase ross-phase GGradient radient Techniques - Techniques - HHigh-latitude Pc5 ULF igh-latitude Pc5 ULF

MMagnetometer agnetometer DDataata

S. T. AblesB. J. Fraser

Centre for Space PhysicsSchool of Mathematical and Physical Sciences

The University of Newcastle AUSTRALIA

University of NewcastleUniversity of NewcastleCentre for Space PhysicsCentre for Space Physics

http://plasma.newcastle.edu.au/plasma

The “Davis Square”The “Davis Square”

Magnetometer Array(Summer operation2002, 2003, 2004)

N (CGM)

Cusp location~75o MLat

Pc5 ULF wavesPc5 ULF waves

7 8-250-200-150-100

-500

50100150200250300350400450 7 8

-450-400-350-300-250-200-150-100

-500

50100150200

UT [Hour]

Y

X

16 January 2003 DAV ZHS VYV RIK

dH/dt

dD/dt

0

5

10

15

20

25

1 4 7 10 13 16 19 22UT [Hour]

DAV-ZHS Cross-phase

Freq

uenc

y [m

Hz]

-90 0 90[Degrees]

Azimuthal pairs of stations were used to produce Cross-phase spectrograms

There are both diurnal and frequency variations in cross-phase

Δ

0

5

10

15

20

25

1 4 7 10 13 16 19 22UT [Hour]

VYV-RIK Cross-phase

Freq

uenc

y [m

Hz]

-90 0 90[Degrees]

Cross-phase spectrogramsfor each azimuthally spaced pair of stations have clear differences.

Particularly 2 hours each side of Local magnetic noon

Δ

IMF control of field line topology – Bz EffectIMF control of field line topology – Bz Effect

-10

0

10

Bz [n

T]

-5

0

5

By [n

T]-500

-400

-300

Vx G

SM

[km

s-1

]

0

0.5

1

Np [c

m-3

]

0

10

20

|B| [

nT]

06:00 07:12 08:24 09:36 10:48 12:000

2

4x 10

11

[W

]

Time

4 6 8 10 12 14 16-50

-40

-30

-20

-10

0

10

20

30

40

505 (2 - 5 mHz)

[deg

rees

]

UT [Hour]

16 January 2003

DAV-ZHS VYV-RIK

The The ФФ5 index: 5 index: Phase Phase difference between 2 azimuthally difference between 2 azimuthally

spaced stationsspaced stations

Closed field lines

IMF control of field line topology – Bz~0IMF control of field line topology – Bz~0

4 6 8 10 12 14 16

-70

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

70

5 (2 - 5 mHz)

24 January 2003

[deg

rees

]

DAV-ZHS VYV-RIK

UT [Hour]

-10

0

10

Bz [n

T]

-10

0

10

By [n

T]-800

-600

-400

Vx G

SM

[km

s-1

]

2

4

6N

p [cm

-3]

0

10

20

|B| [

nT]

06:00 07:12 08:24 09:36 10:48 12:000

5

10x 10

11

[W

]

Time

Closed field linesAnti-sunward azimuthal motion

IMF control of field line topology – Bz NegativeIMF control of field line topology – Bz Negative

4 6 8 10 12 14 16-40

-30

-20

-10

0

10

20

30

405 (2 - 5 mHz)

25 January 2003

[deg

rees

]

UT [Hour]

DAV-ZHS VYV-RIK

-10

0

10

Bz [n

T]

-10

0

10

By [n

T]-900

-800

-700

-600

Vx G

SM

[km

s-1

]

0

2

4N

p [cm

-3]

0

10

20

|B| [

nT]

06:00 07:12 08:24 09:36 10:48 12:000

5

10x 10

11

[W

]

Time

Open field linesconvective motion

IMF control of field line topology – Bz VariableIMF control of field line topology – Bz Variable

-10

0

10

Bz [n

T]

-10

0

10

By [n

T]

-500

-400

-300

Vx GSM [k

m s

-1]

0

5

10N

p [c

m-3

]

0

10

20

|B| [nT

]

06:00 07:12 08:24 09:36 10:48 12:000

5x 10

11

[W

]

Time

4 6 8 10 12 14 16

-70

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

70

15 January 2003

5 (2 - 5 mHz)

[deg

rees

]

UT [Hour]

DAV-ZHS VYV-RIK

Mixed - 0pen-closed field lines