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Perturbations of the terrestrial low ionosphere caused by solar flares. Aleksandra Nina Institute of Physics, Belgrade, Serbia. Contents. Ionosphere Significance of its study VLF signals – “ionospheric probes” Belgrade VLF station Analyze of low ionosphere response to the solar X-flares. - PowerPoint PPT Presentation
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Perturbations of Perturbations of the terrestrial low the terrestrial low ionosphere caused ionosphere caused
by solar flaresby solar flares
Aleksandra NinaInstitute of Physics, Belgrade, Serbia Institute of Physics, Belgrade, Serbia
ContentsContents
• Ionosphere
• Significance of its studySignificance of its study
• VLF signals – “ionospheric probes”VLF signals – “ionospheric probes”
• Belgrade VLF station
• Analyze of low ionosphere response to the solar X-flares
IntroductionIntroduction
• Terrestrial ionosphere• Methods• This talk: experimental and
theoretical research of the perturbations of low ionosphere
(D region)
Significance Significance • ScienceScience
- ionospheric diagnostics
- study of physical and chemical processes
- detection of different pure natural and man-induced events:
1. processes in the Sun
2. processes in the outer spaces
3. processes in the Earth
• TelecommunicationsTelecommunications• - radio communications,
• - planned networks of mobile communications satellites, • - high precision applications of global navigation satellite systems,
etc.
Solar flares and CMEGRB
Lightning Terrestrial Gamma-Ray FlashesNuclear testsEarthquakes Vulcan eruptions
VLF signals – VLF signals – “ionospheric probes”“ionospheric probes”
• Numerical programs: LWPCLWPC, ModeFinderModeFinder
• Advantage: - continual emission - large space that can be analyzed• VLF networks -transmitters -receivers: AWESOMEAWESOME,
AbsPALAbsPAL, SAVNETSAVNET, AARDDVARKAARDDVARK
Belgrade VLF station on Belgrade VLF station on Institute of Physics Institute of Physics
• AbsPalAbsPal- electrical antenna- works as of 2004- simultaneously records 6
signals • AWESOMEAWESOME((Atmospheric Weather Electromagnetic System for Observation Modeling and Education))- two magnetic loop antennas- works as of 2008- simultaneously records 15
signals VLF receiver systems
at Belgrade station
AbsPALAbsPAL AWESOMEAWESOME
Solar X-flare perturbationsSolar X-flare perturbations• Theoretical model: Wait’s model of ionosphere:Wait’s model of ionosphere: reflection height H’ and sharpness β• Numerical program for simulation VLF
signal propagation:
LWPCLWPC (Long-Wave Propagation Capability)::- Input parameters: β and H’ - Output: ALWPC and PLWPC
- Unperturbed ionosphere:
β = 0.3 km-1 H’=74 km
- Perturbed ionosphere:
determination of β and H’
14:05 14:10 14:15 14:20 14:25
52
54
56
58
60
24
26
28
30
10-6
10-5
14:05 14:10 14:15 14:20 14:25
Time (UT)
rec (
o)
Are
c (d
B)
I(W
/m2 )
GOES-15 fit
14:05 14:10 14:15 14:20 14:25
0,3
0,4
0,5
0,6
68
70
72
74
14:05 14:10 14:15 14:20 14:25
(k
m-1)
t (UT)
modeling fit
H' (
km)
modeling fit
Case: -February 18th, 2011
- Recording:- GOES-15 satellite- Belgrade AWESOME receiver- DHO (Germany) transmitter (23.4 kHz) 14:05 14:10 14:15 14:20 14:25
109
1010
1011
N (m
-3)
Time (UT)
httHt eehtN 15.0'131043.1),(
recLWPC AA recLWPC PP
Ionospheric response Ionospheric response (preliminary results)(preliminary results)
G(t) – electron gain rate
L(t) – electron loss rate
Upper half of D region:
tLtGdt
dN
)()()( 00 tItIKPtPtG sss
tNttRtL eff2
P(t) – photo-ionization rateR(t) – recombination rateI(t) – radiation flux by satelliteαeff – effective recombination coefficientKs – coefficient (dependent on energy interval of data registered by satellite)
14:05 14:10 14:15 14:20 14:25
0
1x1010
2x1010
3x1010
4x1010
5x1010
6x1010
dN
/dt (m
-3s-1
)
Time (UT)
total P R
I II III
I - Quasi equilibrium regime
II - Photo-ionization regime
III - Recombination regime
ConclusionsConclusions• The applications of the low ionospheric
investigations in science and information technologies
• Research of low ionosphere by VLF waves• Presentation of Belgrade VLF station• Experimental and theoretical analyzes of the low
ionospheric response to particular solar X-flares - electron concentration - electron gain and electron loss rates (preliminary results)
PerturbersPerturbers• Solar radiation
- regular variation
- transient variations
• Outer space
• Terrestrial
21:30:00 21:30:20 21:30:40 21:31:00
58.0
58.5
59.0
59.5
-130
-125
-120
-11521:30 21:30 21:30 21:31
Am
plit
ud
e (
dB
)
NAA
GRB December 27th, 2004
Ph
ase
(o)
Time (UT)00:00 04:00 08:00 12:00 16:00 20:00 24:0010
20
30
40
10
20
30
40
10
20
30
40
10
20
30
4000:00 04:00 08:00 12:00 16:00 20:00 24:00
Time (UT)
Mart 21, 2011 Mart 22, 2011 Mart 23, 2011
Am
plit
ud
e (
dB
)
December 21, 2010 December 22, 2010 December 23, 2010
September 22, 2010 September 23, 2010 September 24, 2010
Jun 13, 2010 Jun 19, 2010 Jun 20, 2010
DHO
HESSI
06:00 08:00 10:00 12:00 14:00 16:000
5
10
15
20
10
20
30
0
5
10
15
2006:00 08:00 10:00 12:00 14:00 16:00
Am
plit
ude (
dB
)
Time (UT)
NAA
DHO
16_February_2011
1-8A GOES-15
Inte
nsi
ty (
10-6
W/m
2 )
SGR 1806-20
00:42 00:44 00:46 00:48
-170
-165
-160
-155
18
19
20
21
-160
-155
-150
-145
-140
-135
23
24
25
26
2700:42 00:44 00:46 00:48
Ph
ase
(o)
Time (UT)
GQD
Am
plit
ud
e (
dB
)
GQD
Ph
ase
(o) DHO
Am
plit
ud
e (
dB
)
DHO