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Results of waveform analysis in CHIBIS SAS3 burst VLF records

Results of waveform analysis in CHIBIS SAS3 burst VLF records. Péter Steinbach 1,3 ; Csaba Ferencz 1 ; János Lichtenberger 1 ; Orsolya E. Ferencz 1 ; Péter Szegedi 2 1 Space Research Group, Eötvös Univ., Dept. of Geopysics and Space Sci., Budapest, Hungary, spacerg@sas.elte.hu , +361 372 2906

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Results of waveform analysis in CHIBIS SAS3 burst VLF records

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  1. Results of waveform analysis in CHIBIS SAS3burst VLF records Péter Steinbach1,3; Csaba Ferencz1; János Lichtenberger1; Orsolya E. Ferencz1; Péter Szegedi2 1 Space Research Group, Eötvös Univ., Dept. of Geopysics and Space Sci., Budapest,Hungary,spacerg@sas.elte.hu,+361 372 2906 2 BL ELECTRONICS, Solymár, Hungary 3 MTA-ELTE Research Group for Geology, Geophys. and Space Sci. (Hun. Acad. Sci.),Budapest, Hungary

  2. PSA-SAS3 VLF waveform recordings Fs: 78125 Hz 2012.03.01-2013.12.23 ~ 1350 burst data segment E electric – ch0, overall ~ 173 minutes Bz magnetic – ch5, overall ~ 116 minutes

  3. PSA-SAS3 VLF waveform recordings Fs: 78125 Hz 2012.03.01-2013.12.23 ~ 1350 burst data segment E electric – ch0, overall ~ 173 minutes Bz magnetic – ch5, overall ~ 116 minutes daytime, nighttime and twilight orbits

  4. electric CH0 DAY NIGHT Bz magnetic CH5 DAY NIGHT

  5. ○main focus : reveal upward propagation characteristics of signals from the atmosphere / ionosphere (location of primary wave sources) , including determination of probable 3D topology of ionospheric ELF/VLF wave propagation, conform to observations – lightning impulses (whistlers) are perfect tools for that (coherent signal, known excitation, strong)

  6. Chibis max. geographic latitudes L=3.5 100 km altitude geomagnetic field lines Earth surface L=2.0 recording fact #1: ionospheric whistler dispersions depend on geomagnetic latitudes; L=1.05 L=1.3 CHIBIS-M E-field ch0 2012.10.20 12:47:08 UT+3 3:50 LT 270.9E 19.24N geographic mlat: 30.3° geomagnetic D0 dispersion: 1.8 s½ L=1.08 geomagnetic equator CHIBIS-M Bz ch5 2012.07.21 23:22:20 UT+3 3:33 LT 107.8E 2.6S geographic mlat: 11.5° geomagnetic D0 dispersion: 2.5 s½ CHIBIS-M E-field ch0 2012.10.24 06:25:01 UT+3 3:13 LT 317.1E 4.8N geographic mlat: 0.8° geomagnetic D0 dispersion: 14.5 s½

  7. Chibis max. geographic latitudes L=3.5 100 km altitude geomagnetic field lines Earth surface L=2.0 recording fact #1: ionospheric whistler dispersions depend on geomagnetic latitudes; maximum D0 dispersions of 0+ whistlers at the equator L=1.05 L=1.3 CHIBIS-M E-field ch0 2012.10.20 12:47:08 UT+3 3:50 LT 270.9E 19.24N geographic mlat: 30.3° geomagnetic D0 dispersion: 1.8 s½ L=1.08 geomagnetic equator CHIBIS-M Bz ch5 2012.07.21 23:22:20 UT+3 3:33 LT 107.8E 2.6S geographic mlat: 11.5° geomagnetic D0 dispersion: 2.5 s½ CHIBIS-M E-field ch0 2012.10.24 06:25:01 UT+3 3:13 LT 317.1E 4.8N geographic mlat: 0.8° geomagnetic D0 dispersion: 14.5 s½

  8. recording fact #2: ionospheric whistlers often appear as whistler pairsat low geomagnetic latitudes; Chibis CH0 2013.09.05. 05:11:33 UT+3 25.04 W; 15.68 N; geom.lat: 2.75, L: 1.09

  9. 2nd trace of whistler pairs Hughes and Rice, JASTP, 59, 10, 1997 ● whistlers crossed the ionosphere fall in two distinct classes ● their dispersion values strongly depend on magnetic latitude of the satellite, (and on other factors, like LT too…) Δ day ○ night O+ whistlers

  10. #3 What theory/modeling tells?

  11. TASK: determination of most probable sferic entry point at the bottom of the ionosphere TOOLS: oblique UWB (real, time-domain waveform) code IRI2007 IGRF10 Waveform determined by four parameters: (average) plasma- and gyro-frequency, length of the path, and angle between k and B MODEL: deterministic field&medium, straight path between ionosphere ‘entry point’ and satellite

  12. fractional hop (O+) whistler in Chibis Bz – CH5 waveform data 2012.07.2123:23:39 UT+3 110.36 E; 1.11N, mlat: 6.74S

  13. sub-satellite o: 110.36 E; 1.11N geom.lat: 6.74S, L: 1.09, best fit *, field line footprint @100km □: 110.27E; 7.99S whistler dispersion: 2.7 s½ geographic latitude * geographic longitude

  14. best fit * sub-satellite point field line footprint * geographic latitude geographic longitude

  15. L=3.5 L=2.0 L=1.05 L=1.3 ● ionospheric propagation is necessarily oblique; ● path falls most probably in geomagnetic meridian plane; ● paths follows minimum propagation time condition; ● ionosphere entry point falls between sub-satellite and field line footprint positions ● at the magnetic equator the topology is symmetric → whistler pairs L=1.08 geomagnetic equator

  16. L=3.5 formation of low latitude whistler pairs, composed by a 1st trace (0+) and a 2nd with larger dispersion, due to longer, large-angle propagation. L=2.0 L=1.05 L=1.3 ‘forbidden’ source directions at local perpendicular L=1.08 geomagnetic equator ● at the magnetic equator the topology is symmetric

  17. sequence of low-latitude whistler pairs, CHIBIS-M, electric sensor (ch0) 2012.12.01. 18:51:03UT 93.48E;8.87N L=1.08

  18. 3D modeling of 2nd trace entry point of whistler pair □ * low latitude whistler pairs in Chibis E – CH0 waveforms 2013.09.05 05:11:33 UT+3 25.04 W; 15.68 N; geom.lat: 2.75, L: 1.09 geographic latitude ● Arc shaped, no clear best fit entry position – model limitation due to straight path geographic longitude

  19. sequence of whistler groups with same structure, with dispersion (16 s½) according to 2nd traces in pairs CHIBIS-M, electric sensor (CH0) 2013.09.09. 01:23:21 UT+3 9.33 E; 16.1N; mlat: 3.71; L=1.08

  20. satellite: 9.33 E; 16.1N; mlat: 3.71; L=1.08 ●

  21. D0: 5.4 s½, 6.5 s½ D0: 18.5 s½ D0: 31 s½ New observation: fractional-hop whistler TRIPLET, (or more..) 2012.12.0121:51:03 UT+3 93.48 E; 8.87 N; magnetic latitude: 0.07 - equator

  22. two consecutive fractional-hop whistler TRIPLETs 2012.09.19 00:50:31 UT +3 267.78 E; 23.24 N; mlat: 34

  23. two groups of whitler triplets in Chibis-M CH0 waveform record 2013.01.03. 02:49:50 UT+3 1.26 E; 5.47 N, mlat:-0.9

  24. two groups of whitler triplets in Chibis-M CH0 waveform record 2013.01.03. 02:49:50 UT+3 1.26 E; 5.47 N, mlat:-0.9

  25. two groups of whitler triplets in Chibis-M CH0 waveform record 2013.01.03. 02:49:50 UT+3 1.26 E; 5.47 N, mlat:-0.9

  26. two groups of whitler triplets in Chibis-M CH0 waveform record 2013.01.03. 02:49:50 UT+3 1.26 E; 5.47 N, mlat:-0.9

  27. two groups of whitler triplets in Chibis-M CH0 waveform record 2013.01.03. 02:49:50 UT+3 1.26 E; 5.47 N, mlat:-0.9

  28. vanellus / lapwing / чибис / bíbic Thank you for your attention! Благодарю вас за внимание!

  29. DEMETER VLF, 2004.08.26 03:33:02 UT two groups of whitler triplets in Chibis-M CH0 waveform record 2013.01.03. 02:49:50 UT+3 1.26 E; 5.47 N, mlat:-0.9

  30. DAYTIME PASS NIGHTTIME PASS

  31. Determination of most probable sferic entry point at the bottom of the ionosphere oblique UWB code IRI2007 IGRF10 Comparison of modeled, trans-ionospheric whistler traces to recorded one. -> geographic distribution of residuals (similarity values), and best fit entry point at residual minima; latitude dependent topology of prop. in the ionosphere

  32. L=1.08 equator very simplified cartoon for VLF wave propagation in the ionosphere ● waves reach the satellite along paths with minimum propagation time; this is represented by the path between the shortest, but high angle (vertical) and the longer, field aligned (longitudinal) directions

  33. L=1.08 equator intropical regions the magnetic field governed propagation topology is symmetric ● at equatorial and low magnetic latitudes occurrences of fractional-hop whistlers with two dispersion classes are expected

  34. A B C low-latitude whistler triplet pair, CHIBIS-M, electric field sensor (ch0) 2012.09.19. 00:50:31UT+3 267.79E;23.24N mlat=33.91 L=1.56 calculated D0 dispersions are A: 1.8 s½, B: 10.8 s½, C: 21.2 s½

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