foreshock significance in generation of ulf waves alex angelo mentor-olga gutynska
DESCRIPTION
Ion ForeshockTRANSCRIPT
Foreshock Significance in Generation of ULF WavesAlex AngeloMentor-Olga Gutynska
ULF Waves• AKA Magnetic Pulsations
• 1 mHz to 1 Hz
• Pc versus Pi
• Variety of events thought to be energy inputs– Kevin-Helmholtz Instabilities– Reconnection – Flux Transfers
IONOSPHERE
EARTH
ULF WAVES
STANDING WAVES
Ion Foreshock
Importance of ULF Waves• Oscillations in the magnetosphere disturb the ionosphere
• Effect the total electron count (TEC) fluctuations (0.005% to 0.1%)
• While often regarded as insignificant for high frequency EM signal propagation, with improving resolution/signal ULF oscillation becomes detectable – Over-the-horizon radar, GPS, magnetic anomaly detection – Preventing future improvements– Constant noise
• Radio astronomy – LO-FAR
• Understand what’s happening in space
Methods
Start of interval End of interval
10/30/07
10/30/07
10/30/07
FFT• Broke intervals into
ten minute or one hour intervals
• Looked at Moments for x-components of velocity
• Looked at ESA for magnetic fluctuations
• Preformed Fast Fourier Transformation to find frequency and hence period
• Calculated periods• A: 299.35895 s• D: 200.06446 s• E: 199.89372 s
0 to 5
0
50 to
100
100 t
o 150
150 t
o 200
200 t
o 250
250 t
o 300
300 t
o 350
0
200400600800
10001200
Periods Based on Magnetic Field Fluctuations- 10 Minute Inter-
vals
MagnetosphereSolar Wind Foreshock
Period RangeNum
ber
of 1
0 M
inut
e Ev
ents
0 to 2
00
200 t
o 400
400 t
o 600
600 t
o 800
800 t
o 100
0
1000
to 12
00
1200
to 14
00
1400
to 16
00
1600
to 18
000
50
100
150
200
Periods Based on X-Components of Velocity – One Hour Intervals
MagnetosphereSolar Wind Foreshock
Period RangeNum
ber
of H
our
Even
ts0 t
o 200
200 t
o 400
400 t
o 600
600 t
o 800
800 t
o 100
0
1000
to 12
00
1200
to 14
00
1400
to 16
00
1600
to 18
000
20406080
100120140160
Periods Based on Magnetic Field Fluctuations- One Hour Intervals
MagnetosphereSolar Wind Foreshock
Period RangeNum
ber
of H
our
Even
ts
0 to 5
0
50 to
100
100 t
o 150
150 t
o 200
200 t
o 250
250 t
o 300
300 t
o 350
0
200
400
600
800
1000
Periods Based on X-Components of Velocity - 10 Minute Intervals
MagnetosphereSolar Wind Foreshock
Period Range
Num
ber
of 1
0 M
inut
e Ev
ents
Period AveragesSolar Wind: 208.792Magnetosphere: 267.419