Characteristics of equatorial plasma
bubbles observed by TEC map over
South America
Barros, D.; Takahashi, H.; Wrasse, C. M.; Figueiredo, C. A.
Instituto Nacional de Pesquisas EspaciaisSao Jose dos Campos, Sao Paulo, Brazil
April/2017
Diego Barros — April/2017 plasma bubles observed by tec map 1
Outline
1. IntroductionWhat are plasma bubbles?
2. Instrumentation and MetodologyTECdTEC
3. ResultsCharacteristics of plasma bubbles observed by TEC map
4. Summary
Diego Barros — April/2017 plasma bubles observed by tec map 2
Outline
1. IntroductionWhat are plasma bubbles?
2. Instrumentation and MetodologyTECdTEC
3. ResultsCharacteristics of plasma bubbles observed by TEC map
4. Summary
Diego Barros — April/2017 plasma bubles observed by tec map 2
Outline
1. IntroductionWhat are plasma bubbles?
2. Instrumentation and MetodologyTECdTEC
3. ResultsCharacteristics of plasma bubbles observed by TEC map
4. Summary
Diego Barros — April/2017 plasma bubles observed by tec map 2
Outline
1. IntroductionWhat are plasma bubbles?
2. Instrumentation and MetodologyTECdTEC
3. ResultsCharacteristics of plasma bubbles observed by TEC map
4. Summary
Diego Barros — April/2017 plasma bubles observed by tec map 2
Outline
1. IntroductionWhat are plasma bubbles?
2. Instrumentation and MetodologyTECdTEC
3. ResultsCharacteristics of plasma bubbles observed by TEC map
4. Summary
Diego Barros — April/2017 plasma bubles observed by tec map 2
INTRODUCTION
Diego Barros — April/2017 plasma bubles observed by tec map 3
Introduction
What are plasma bubbles?
Plasma Bubbles are equatorial plasma irregularities;
Are characterized to be a depletion of the ionosphericplasma density along the magnetic field lines;
It has serious implication in trans-ionosphericcommunications and navigation systems.
Diego Barros — April/2017 plasma bubles observed by tec map 4
Introduction
What are plasma bubbles?
Plasma Bubbles are equatorial plasma irregularities;
Are characterized to be a depletion of the ionosphericplasma density along the magnetic field lines;
It has serious implication in trans-ionosphericcommunications and navigation systems.
Diego Barros — April/2017 plasma bubles observed by tec map 4
Introduction
What are plasma bubbles?
Plasma Bubbles are equatorial plasma irregularities;
Are characterized to be a depletion of the ionosphericplasma density along the magnetic field lines;
It has serious implication in trans-ionosphericcommunications and navigation systems.
Diego Barros — April/2017 plasma bubles observed by tec map 4
Introduction
Plasma bubbles signaturesAll Sky imager
EMBRACE
VHF radar
De Paula et al. (2011)Photometer
Pimenta (2005)
Diego Barros — April/2017 plasma bubles observed by tec map 5
Introduction
Plasma bubbles signaturesAll Sky imager
EMBRACE
VHF radar
De Paula et al. (2011)Photometer
Pimenta (2005)
Diego Barros — April/2017 plasma bubles observed by tec map 5
Introduction
Plasma bubbles signaturesAll Sky imager
EMBRACE
VHF radar
De Paula et al. (2011)Photometer
Pimenta (2005)
Diego Barros — April/2017 plasma bubles observed by tec map 6
Introduction
Plasma bubbles signatures
Rockets - Langmuir probe
Muralikrishna (2006)
Ionosonde
Pimenta (2005)
Diego Barros — April/2017 plasma bubles observed by tec map 7
Introduction
Plasma bubbles signatures
Rockets - Langmuir probe
Muralikrishna (2006)
Ionosonde
Pimenta (2005)
Diego Barros — April/2017 plasma bubles observed by tec map 7
INSTRUMENTATION ANDMETODOLOGY
Diego Barros — April/2017 plasma bubles observed by tec map 8
Instrumentation and Metodology
Measurement limitations
Most of the techniques mentioned above are not able to monitorplasma bubbles continuously in a sufficiently large twodimensional area.
All-sky imager - Depend on favorable weather conditions;
VHF radar and ionosonde - Cannot cover a wide range;
Rocket and Satellite - Only in situ measeruments;
Rocket - Sporadic launching.
Diego Barros — April/2017 plasma bubles observed by tec map 9
Instrumentation and Metodology
Measurement limitations
Most of the techniques mentioned above are not able to monitorplasma bubbles continuously in a sufficiently large twodimensional area.
All-sky imager - Depend on favorable weather conditions;
VHF radar and ionosonde - Cannot cover a wide range;
Rocket and Satellite - Only in situ measeruments;
Rocket - Sporadic launching.
Diego Barros — April/2017 plasma bubles observed by tec map 9
Instrumentation and Metodology
Measurement limitations
Most of the techniques mentioned above are not able to monitorplasma bubbles continuously in a sufficiently large twodimensional area.
All-sky imager - Depend on favorable weather conditions;
VHF radar and ionosonde - Cannot cover a wide range;
Rocket and Satellite - Only in situ measeruments;
Rocket - Sporadic launching.
Diego Barros — April/2017 plasma bubles observed by tec map 9
Instrumentation and Metodology
Measurement limitations
Most of the techniques mentioned above are not able to monitorplasma bubbles continuously in a sufficiently large twodimensional area.
All-sky imager - Depend on favorable weather conditions;
VHF radar and ionosonde - Cannot cover a wide range;
Rocket and Satellite - Only in situ measeruments;
Rocket - Sporadic launching.
Diego Barros — April/2017 plasma bubles observed by tec map 9
Instrumentation and Metodology
Measurement limitations
Most of the techniques mentioned above are not able to monitorplasma bubbles continuously in a sufficiently large twodimensional area.
All-sky imager - Depend on favorable weather conditions;
VHF radar and ionosonde - Cannot cover a wide range;
Rocket and Satellite - Only in situ measeruments;
Rocket - Sporadic launching.
Diego Barros — April/2017 plasma bubles observed by tec map 9
Instrumentation and Metodology
Measurement limitations
Most of the techniques mentioned above are not able to monitorplasma bubbles continuously in a sufficiently large twodimensional area.
All-sky imager - Depend on favorable weather conditions;
VHF radar and ionosonde - Cannot cover a wide range;
Rocket and Satellite - Only in situ measeruments;
Rocket - Sporadic launching.
Diego Barros — April/2017 plasma bubles observed by tec map 9
Instrumentation and Metodology
TEC
TEC = Total Electron Content
TEC =satellite∫receiver
Ne · ds
TECU = 1016 eletrons/m2
Diego Barros — April/2017 plasma bubles observed by tec map 10
Instrumentation and Metodology
TEC
TEC = Total Electron Content
TEC =satellite∫receiver
Ne · ds
TECU = 1016 eletrons/m2
Diego Barros — April/2017 plasma bubles observed by tec map 10
Instrumentation and Metodology
TEC
TEC = Total Electron Content
TEC =satellite∫receiver
Ne · ds
TECU = 1016 eletrons/m2
Diego Barros — April/2017 plasma bubles observed by tec map 10
Instrumentation and Metodology
TEC
TEC = Total Electron Content
TEC =satellite∫receiver
Ne · ds
TECU = 1016 eletrons/m2
Diego Barros — April/2017 plasma bubles observed by tec map 10
Instrumentation and Metodology
GNSS receivers
GNSS network N◦ of satellitesGPS 32
GLONASS 24Galileo 18BDS 22Total 96
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30
-35
-30
-25
-20
-15
-10
-50
5
-35-30
-25-20
-15-10
-50
5 RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
Longitude (o)
Lat
itu
de
(o)
Figueiredo (2017)
Square GPS (2017)
Receivers network N◦ of receiversLISN 30IGS 29
RAMSAC 67RBMC 101Total 227
Diego Barros — April/2017 plasma bubles observed by tec map 11
Instrumentation and Metodology
GNSS receivers
GNSS network N◦ of satellitesGPS 32
GLONASS 24Galileo 18BDS 22Total 96
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30
-35
-30
-25
-20
-15
-10
-50
5
-35-30
-25-20
-15-10
-50
5 RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
Longitude (o)
Lat
itu
de
(o)
Figueiredo (2017)
Square GPS (2017)
Receivers network N◦ of receiversLISN 30IGS 29
RAMSAC 67RBMC 101Total 227
Diego Barros — April/2017 plasma bubles observed by tec map 12
Instrumentation and Metodology
TEC map
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30
-35
-30
-25
-20
-15
-10
-50
5
-35-30
-25-20
-15-10
-50
5
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
RBMC RAMSAC LISN IGS
Longitude (o)
Lat
itu
de
(o)
Diego Barros — April/2017 plasma bubles observed by tec map 13
Instrumentation and Metodology
TEC map
Diego Barros — April/2017 plasma bubles observed by tec map 13
Instrumentation and Metodology
TEC map
Diego Barros — April/2017 plasma bubles observed by tec map 13
Instrumentation and Metodology
TEC map analysis
TEC map can cover almost wholeSouth America and monitor TECvariability.
The spatial resolution varies from50-500 km.
TEC map has a time resolutionof 10 minutes.
Diego Barros — April/2017 plasma bubles observed by tec map 14
Instrumentation and Metodology
TEC map analysis
TEC map can cover almost wholeSouth America and monitor TECvariability.
The spatial resolution varies from50-500 km.
TEC map has a time resolutionof 10 minutes.
Diego Barros — April/2017 plasma bubles observed by tec map 14
Instrumentation and Metodology
TEC map analysis
TEC map can cover almost wholeSouth America and monitor TECvariability.
The spatial resolution varies from50-500 km.
TEC map has a time resolutionof 10 minutes.
Diego Barros — April/2017 plasma bubles observed by tec map 14
Instrumentation and Metodology
TEC map analysis
Linear fitting over the minimumTEC values;
Latitudinal extension;
Inclination = angle between thelinear fitting and the geomagneticfield line.
Diego Barros — April/2017 plasma bubles observed by tec map 15
Instrumentation and Metodology
TEC map analysis
Linear fitting over the minimumTEC values;
Latitudinal extension;
Inclination = angle between thelinear fitting and the geomagneticfield line.
Diego Barros — April/2017 plasma bubles observed by tec map 15
Instrumentation and Metodology
TEC map analysis
Linear fitting over the minimumTEC values;
Latitudinal extension;
Inclination = angle between thelinear fitting and the geomagneticfield line.
Diego Barros — April/2017 plasma bubles observed by tec map 15
Instrumentation and Metodology
TEC map analysis
Linear fitting over the minimumTEC values;
Latitudinal extension;
Inclination = angle between thelinear fitting and the geomagneticfield line.
Diego Barros — April/2017 plasma bubles observed by tec map 15
Instrumentation and Metodology
Keograms
A keogram is a collection of west-east slices of TEC maps displayed in alongitude vs time diagram.
Diego Barros — April/2017 plasma bubles observed by tec map 16
Instrumentation and Metodology
Keograms
A keogram is a collection of west-east slices of TEC maps displayed in alongitude vs time diagram.
Diego Barros — April/2017 plasma bubles observed by tec map 16
Instrumentation and Metodology
Keogram analysis
Zonal drift velocity
vel =x(ti)− x(ti−1)
ti − ti−1[m/s]
Distance between adjacents bubbles
Dis = (xi − xi−1)[km]
Diego Barros — April/2017 plasma bubles observed by tec map 17
Instrumentation and Metodology
Keogram analysis
Zonal drift velocity
vel =x(ti)− x(ti−1)
ti − ti−1[m/s]
Distance between adjacents bubbles
Dis = (xi − xi−1)[km]
Diego Barros — April/2017 plasma bubles observed by tec map 18
Instrumentation and Metodology
Keogram analysis
Zonal drift velocity
vel =x(ti)− x(ti−1)
ti − ti−1[m/s]
Distance between adjacents bubbles
Dis = (xi − xi−1)[km]
Diego Barros — April/2017 plasma bubles observed by tec map 19
Instrumentation and Metodology
We repeate this metodoly for eight different latitudes.
Diego Barros — April/2017 plasma bubles observed by tec map 20
Instrumentation and Metodology
Keograms
We can investigate latitudinal gradients in zonal velocities anddistances in a large spatial range.
Diego Barros — April/2017 plasma bubles observed by tec map 21
Instrumentation and Metodology
Keograms
We can investigate latitudinal gradients in zonal velocities anddistances in a large spatial range.
Diego Barros — April/2017 plasma bubles observed by tec map 21
CHARACTERISTICS OFPLASMA BUBBLES OBSERVED
BY TEC MAP
Diego Barros — April/2017 plasma bubles observed by tec map 22
Characteristics of plasma bubbles - TEC map
TEC map data base
TEC map data were analyzedbetween 11/2012 and01/2016;
Total of 597 nights;
Several plasma bubblessimultaneously.
Diego Barros — April/2017 plasma bubles observed by tec map 23
Characteristics of plasma bubbles - TEC map
TEC map data base
TEC map data were analyzedbetween 11/2012 and01/2016;
Total of 597 nights;
Several plasma bubblessimultaneously.
Diego Barros — April/2017 plasma bubles observed by tec map 23
Characteristics of plasma bubbles - TEC map
TEC map data base
TEC map data were analyzedbetween 11/2012 and01/2016;
Total of 597 nights;
Several plasma bubblessimultaneously.
Diego Barros — April/2017 plasma bubles observed by tec map 23
Characteristics of plasma bubbles - TEC map
TEC map data base
TEC map data were analyzedbetween 11/2012 and01/2016;
Total of 597 nights;
Several plasma bubblessimultaneously.
Diego Barros — April/2017 plasma bubles observed by tec map 23
Characteristics of plasma bubbles - TEC map
Frequency of occurrence of plasma bubbles
The largest number of plasmabubbles extends fromSeptember to March;
No occurrence of plasmabubbles can be seen from Mayto August due to the plasmabubbles criteria discussed.
Diego Barros — April/2017 plasma bubles observed by tec map 24
Characteristics of plasma bubbles - TEC map
Frequency of occurrence of plasma bubbles
The largest number of plasmabubbles extends fromSeptember to March;
No occurrence of plasmabubbles can be seen from Mayto August due to the plasmabubbles criteria discussed.
Diego Barros — April/2017 plasma bubles observed by tec map 24
Characteristics of plasma bubbles - TEC map
Frequency of occurrence of plasma bubbles
The largest number of plasmabubbles extends fromSeptember to March;
No occurrence of plasmabubbles can be seen from Mayto August due to the plasmabubbles criteria discussed.
Diego Barros — April/2017 plasma bubles observed by tec map 24
Characteristics of plasma bubbles - TEC map
Latitudinal extension of the plama bubbles and apex height
The extensions are larger inJanuary and December;
88% of cases the plasma bubblescan develop up to 20◦S.
Diego Barros — April/2017 plasma bubles observed by tec map 25
Characteristics of plasma bubbles - TEC map
Latitudinal extension of the plama bubbles and apex height
The extensions are larger inJanuary and December;
88% of cases the plasma bubblescan develop up to 20◦S.
Diego Barros — April/2017 plasma bubles observed by tec map 25
Characteristics of plasma bubbles - TEC map
Latitudinal extension of the plama bubbles and apex height
The extensions are larger inJanuary and December;
88% of cases the plasma bubblescan develop up to 20◦S.
Diego Barros — April/2017 plasma bubles observed by tec map 26
Characteristics of plasma bubbles - TEC map
Latitudinal extension of the plama bubbles and apex height
The extensions are larger inJanuary and December;
88% of cases the plasma bubblescan develop up to 20◦S.
Diego Barros — April/2017 plasma bubles observed by tec map 26
Characteristics of plasma bubbles - TEC map
Zonal drift velocities
Zonal velocities present a clearlatitudinal gradient;
v = 123 m/s at the Equator;
v = 65 m/s at 35◦S latitude.
Diego Barros — April/2017 plasma bubles observed by tec map 27
Characteristics of plasma bubbles - TEC map
Zonal drift velocities
Zonal velocities present a clearlatitudinal gradient;
v = 123 m/s at the Equator;
v = 65 m/s at 35◦S latitude.
Diego Barros — April/2017 plasma bubles observed by tec map 27
Characteristics of plasma bubbles - TEC map
Zonal drift velocities
Zonal velocities present a clearlatitudinal gradient;
v = 123 m/s at the Equator;
v = 65 m/s at 35◦S latitude.
Diego Barros — April/2017 plasma bubles observed by tec map 27
Characteristics of plasma bubbles - TEC map
Zonal drift velocities
Zonal velocities present a clearlatitudinal gradient;
v = 123 m/s at the Equator;
v = 65 m/s at 35◦S latitude.
Diego Barros — April/2017 plasma bubles observed by tec map 27
Characteristics of plasma bubbles - TEC map
Inter-bubble distances
Inter-bubble distances present aclear latitudinal gradient;
d = 920 km at the Equator;
d = 640 km at 30◦S latitude;
Distances greater than 2000 kmat the Equator.
Diego Barros — April/2017 plasma bubles observed by tec map 28
Characteristics of plasma bubbles - TEC map
Inter-bubble distances
Inter-bubble distances present aclear latitudinal gradient;
d = 920 km at the Equator;
d = 640 km at 30◦S latitude;
Distances greater than 2000 kmat the Equator.
Diego Barros — April/2017 plasma bubles observed by tec map 28
Characteristics of plasma bubbles - TEC map
Inter-bubble distances
Inter-bubble distances present aclear latitudinal gradient;
d = 920 km at the Equator;
d = 640 km at 30◦S latitude;
Distances greater than 2000 kmat the Equator.
Diego Barros — April/2017 plasma bubles observed by tec map 28
Characteristics of plasma bubbles - TEC map
Inter-bubble distances
Inter-bubble distances present aclear latitudinal gradient;
d = 920 km at the Equator;
d = 640 km at 30◦S latitude;
Distances greater than 2000 kmat the Equator.
Diego Barros — April/2017 plasma bubles observed by tec map 28
Characteristics of plasma bubbles - TEC map
Inter-bubble distances
Inter-bubble distances present aclear latitudinal gradient;
d = 920 km at the Equator;
d = 640 km at 30◦S latitude;
Distances greater than 2000 kmat the Equator.
Diego Barros — April/2017 plasma bubles observed by tec map 28
Characteristics of plasma bubbles - TEC map
Inclination of the plasma bubbles against geomagnetic field lines
Geomagnetic field lines;
θ+ = Tilted to the West;
θ− = Tilted to the East.
Diego Barros — April/2017 plasma bubles observed by tec map 29
Characteristics of plasma bubbles - TEC map
Inclination of the plasma bubbles against geomagnetic field lines
Geomagnetic field lines;
θ+ = Tilted to the West;
θ− = Tilted to the East.
Diego Barros — April/2017 plasma bubles observed by tec map 29
Characteristics of plasma bubbles - TEC map
Inclination of the plasma bubbles against geomagnetic field lines
Geomagnetic field lines;
θ+ = Tilted to the West;
θ− = Tilted to the East.
Diego Barros — April/2017 plasma bubles observed by tec map 29
Characteristics of plasma bubbles - TEC map
Inclination of the plasma bubbles against geomagnetic field lines
Geomagnetic field lines;
θ+ = Tilted to the West;
θ− = Tilted to the East.
Diego Barros — April/2017 plasma bubles observed by tec map 29
Characteristics of plasma bubbles - TEC map
Inclination of the plasma bubbles against geomagnetic field lines
Nov./2012 − Jan./2016
Months
Jan Fev Mar Abr Mai Jun Jul Ago Set OutNovDez−12−10
−8
−6
−4
−2
0
2
4
6
8
10
12
Incl
inat
on
(°)
In general, inclination of the plasma bubbles is larger in January andDecember;
∇U = U(0◦) - U(25◦S);
Good agreement with the monthly averaged zonal windgradient calculated from the HWM14.
Diego Barros — April/2017 plasma bubles observed by tec map 30
Characteristics of plasma bubbles - TEC map
Inclination of the plasma bubbles against geomagnetic field lines
Nov./2012 − Jan./2016
Months
Jan Fev Mar Abr Mai Jun Jul Ago Set OutNovDez−12−10
−8
−6
−4
−2
0
2
4
6
8
10
12
Incl
inat
on
(°)
In general, inclination of the plasma bubbles is larger in January andDecember;
∇U = U(0◦) - U(25◦S);
Good agreement with the monthly averaged zonal windgradient calculated from the HWM14.
Diego Barros — April/2017 plasma bubles observed by tec map 30
Characteristics of plasma bubbles - TEC map
Inclination of the plasma bubbles against geomagnetic field lines
Nov./2012 − Jan./2016
Months
Jan Fev Mar Abr Mai Jun Jul Ago Set OutNovDez−12−10
−8
−6
−4
−2
0
2
4
6
8
10
12
Incl
inat
on
(°)
In general, inclination of the plasma bubbles is larger in January andDecember;
∇U = U(0◦) - U(25◦S);
Good agreement with the monthly averaged zonal windgradient calculated from the HWM14.
Diego Barros — April/2017 plasma bubles observed by tec map 30
Characteristics of plasma bubbles - TEC map
Inclination of the plasma bubbles against geomagnetic field lines
Magnetic inclination vs Zonal wind gradient
Months
Jan Feb MarAprMay Jun Jul Aug Sep Oct NovDec−12−10
−8
−6
−4
−2
0
2
4
6
8
10
12
Incl
inat
ion
(°)
−80
−60
−40
−20
0
20
40
60
80
Vel
oci
ty (
m/
s)In general, inclination of the plasma bubbles is larger in January andDecember;
∇U = U(0◦) - U(25◦S);
Good agreement with the monthly averaged zonal windgradient calculated from the HWM14.
Diego Barros — April/2017 plasma bubles observed by tec map 30
Summary
EPBs occurred mainly from September to March. The latitudinal extensionof the EPBs is larger for the months of January and December. In 88% ofthe cases the EPBs developed up to 20◦S, indicating that the apex heightwas of 777 km altitude;
EPB zonal drift velocities presented a clear latitudinal gradient varying from123m/s at the Equator to 65m/s at 35◦S;
The inter-bubble distances also showed a clear latitudinal gradient varyingfrom 920 km at the Equator to 640 km at 30◦S;
The latitudinal extension of EPBs occasionally presents a significantinclination against the geomagnetic field lines;
Diego Barros — April/2017 plasma bubles observed by tec map 31
Summary
EPBs occurred mainly from September to March. The latitudinal extensionof the EPBs is larger for the months of January and December. In 88% ofthe cases the EPBs developed up to 20◦S, indicating that the apex heightwas of 777 km altitude;
EPB zonal drift velocities presented a clear latitudinal gradient varying from123m/s at the Equator to 65m/s at 35◦S;
The inter-bubble distances also showed a clear latitudinal gradient varyingfrom 920 km at the Equator to 640 km at 30◦S;
The latitudinal extension of EPBs occasionally presents a significantinclination against the geomagnetic field lines;
Diego Barros — April/2017 plasma bubles observed by tec map 31
Summary
EPBs occurred mainly from September to March. The latitudinal extensionof the EPBs is larger for the months of January and December. In 88% ofthe cases the EPBs developed up to 20◦S, indicating that the apex heightwas of 777 km altitude;
EPB zonal drift velocities presented a clear latitudinal gradient varying from123m/s at the Equator to 65m/s at 35◦S;
The inter-bubble distances also showed a clear latitudinal gradient varyingfrom 920 km at the Equator to 640 km at 30◦S;
The latitudinal extension of EPBs occasionally presents a significantinclination against the geomagnetic field lines;
Diego Barros — April/2017 plasma bubles observed by tec map 31
Summary
EPBs occurred mainly from September to March. The latitudinal extensionof the EPBs is larger for the months of January and December. In 88% ofthe cases the EPBs developed up to 20◦S, indicating that the apex heightwas of 777 km altitude;
EPB zonal drift velocities presented a clear latitudinal gradient varying from123m/s at the Equator to 65m/s at 35◦S;
The inter-bubble distances also showed a clear latitudinal gradient varyingfrom 920 km at the Equator to 640 km at 30◦S;
The latitudinal extension of EPBs occasionally presents a significantinclination against the geomagnetic field lines;
Diego Barros — April/2017 plasma bubles observed by tec map 31
Summary
EPBs occurred mainly from September to March. The latitudinal extensionof the EPBs is larger for the months of January and December. In 88% ofthe cases the EPBs developed up to 20◦S, indicating that the apex heightwas of 777 km altitude;
EPB zonal drift velocities presented a clear latitudinal gradient varying from123m/s at the Equator to 65m/s at 35◦S;
The inter-bubble distances also showed a clear latitudinal gradient varyingfrom 920 km at the Equator to 640 km at 30◦S;
The latitudinal extension of EPBs occasionally presents a significantinclination against the geomagnetic field lines;
Diego Barros — April/2017 plasma bubles observed by tec map 31
Thank you!
Diego Barros — April/2017 plasma bubles observed by tec map 32