Incoherent and Coherent Scatter Radars: Jicamarca examples

Transcription

1 Incoherent and Coherent Scatter Radars: Jicamarca examples R. F Woodman Radio Observatorio de Jicamarca, Instituto Geofísico del Perú, Lima Equatorial Aeronomy 1

2 Early History Equatorial Aeronomy 2

3 Model of the satellite, with its long antennae. Credit: TASS SPUTNIK Copyright 1997 (1957) The New York Times Company Equatorial Aeronomy 3

4 Incoherent Scatter History Gordon (1958) Proposes the technique Equatorial Aeronomy 4

5 Equatorial Aeronomy 5

6 Incoherent Scatter History Gordon (1958) proposes the technique Bowles (1958) carries first succesfull experiment. Electrons do not control the spectrum. The ions do. Equatorial Aeronomy 6

7 Incoherent Scatter History Gordon (1958) proposes the technique Bowles (1958) carries first succesfull experiment. Electrons do not control the spectrum. It is the ions. Fejer (1960), Dougherty and Farley (1960,1963), Salpeter(1960), Hagfors (1961), Rosenbluth and Rostoker (1962), Farley (1966), Woodman (1967), develop the theory. (See Hagfors, EISCAT Summer School 2003, for a comprehensive introduction). Equatorial Aeronomy 7

8 Let * h τ h h C ( ) = S ( t) S ( t + τ) ρh (, r τ) = n(,)( x t n x + r, t + τ) and ρˆ h( kb, τ) = d Vρh( r, τ) e then C ( τ) ρˆ ( k, τ) h h B where kb = ki ks ikr. Equatorial Aeronomy 8

9 C ( τ) ρˆ ( k, τ) h h B Discussion The statistics of the radar signal received is a (instrumental) functional of the fluctuation statistics of the medium. Of all the spatial Fourier components of the fluctuations, only one component, that corresponding to k B, contributes to the radar signal. For IS, plasma fluctuation theory provides us with an analytical expression for ρˆh kb τ ρˆh kb τ ne ni Te Ti v v B (, ) (, ;,[ ],,,,, ) Equatorial Aeronomy 9

10 Physical processes responsible for the fluctuations Discrete nature of electrons Discrete nature of ions Particles, electrons and ions, interact with the background plasma. Dressed particle approach Equatorial Aeronomy 10

11 Measurable parameters (For all ionospheric altitudes and time) ρˆh( kb, τ) ρˆh( kb, τ; ne, [ ni ], Te, Ti, v, v, B) Electron density, Ionic composition Electron temperature Ion temperature Drift velocities= Electric field Drag velocity (parallel to B) (not at Jicamarca) B Equatorial Aeronomy 11

12 ISR Theory ( ) Equatorial Aeronomy 12

13 ISR Theory ( ) Equatorial Aeronomy 13

14 ISR Theory ( ) Equatorial Aeronomy 14

15 ISR Theory ( ) Equatorial Aeronomy 15

16 ISR Theory ( ) Equatorial Aeronomy 16

17 ISR Theory ( ) Equatorial Aeronomy 17

18 ISR Theory ( ) Equatorial Aeronomy 18

19 Equatorial Aeronomy 19

20 Introduction Built in 1961 Antenna of 300m x 300 m 3 txs of 1.5 MW each Multiple rx capability Equatorial Aeronomy 20

21 Equatorial Aeronomy 21

22 Equatorial Aeronomy 22

23 Woodman and Hafgfors, 1971 Equatorial Aeronomy 23

24 Woodman, 1971 Equatorial Aeronomy 24

25 Equatorial Aeronomy 25

26 Woodman and Hafgfors, 1971 Equatorial Aeronomy 26

27 Woodman, 1971 Equatorial Aeronomy 27

28 Ne Te Ti Equatorial Aeronomy 28

29 ISR example (1) Oblique mode Hybrid 1 It combines the traditional Faraday Double Pulse mode with alternating code mode. Allowing use of the available duty cycle and therefore better measurements and higher altitudinal coverage than before! Note: There are no E region measurements! Equatorial Aeronomy 29

30 ISR example (2) Oblique mode Hybrid 2: Long Pulse + Faraday Equatorial Aeronomy 30

31 ISR example (3) Perpendicular Mode East-West Drift Equatorial Aeronomy 31

32 ISR example (4) Perpendicular Mode East-West Drift (Kudeki et al. [1999]) Combined measurements of Incoherent and coherent scatter measurements. Precise measurements allow the observation of F region vortex. We expect to improve those measurements with the addition of digital rxs at Jicamarca with more dynamic range. Equatorial Aeronomy 32

33 ISR example (5) Perpendicular Mode -Differential Phase (Kudeki et al. [2003], Feng et al. [2003], Feng et al. [2004]) This new mode allows the simultaneous measurements of ionospheric drifts and densities. Relative densities are obtained from total power measurements Absolute measurements are obtained from the differential phase measurements (self calibration) or from the ionosonde measurements. Equatorial Aeronomy 33

34 ISR example (6) Perpendicular Mode Differential Phase (Kudeki et al. [2003] Feng et al. [2003] Feng et al. [2004]) Simultaneous measurements of vertical drifts and densities. Future efforts will be devoted to get simultaneously: zonal drifts temperatures Equatorial Aeronomy 34

35 JRO Modes Coherent Scatter Radar ISR Equatorial Aeronomy 35

36 Additional antennas and systems Bistatic Tx Main COCO-Hysell Yagi array SOUSY Digisonde Tx Mattresses COCO-100

37 MST Spectra (from Woodman [2002]) Equatorial Aeronomy 37

38 MST Winds Equatorial Aeronomy 38

39 ESF echoes (from Woodman and Chau [2001]) Equatorial Aeronomy 39

40 CSR-JULIA: Multimode Ionospheric Observations Jicamarca Unattended Long term Investigations of the Atmosphere (Balsley, 1993) JULIA concept: Low-power and long-term measurements at Jicamarca 1500 ESF and ESF East Quarter EEJ (Oblique Yagis) ESF and EEJ East Quarter ESF and EEJ West Quarter EEJ (COCO) 150 km echoes (Main vertical) EEJ (COCO) ESF and EEJ West Quarter Equatorial Aeronomy 40

41 CSR- JULIA: Parameters from ESF and 150-km echoes ESF: Interferometry 150-km:Dual beam Under validation! Equatorial Aeronomy 41

42 CSR- Bistatic Mode (1) This bistatic mode complements Jicamarca capabilities. E region measurements using ISR are not possible at JRO due to the presence of strong EEJ clutter. Technique was introduced by Hysell and Chau [2001] using very small systems. Only daytime observations were made at the time. The technique takes advantage of the strong EEJ echoes to scatter part of the signal transmitted. Density profiles are obtained by measuring the Faraday rotation of the scatter signal as a function of range. Equatorial Aeronomy 42

43 CSR- Bistatic Mode (3) - New permanent system More antennas More tx power Digital rx and DDS, using GPS synchronized clocks for range and frequency stability. Expect to operate continuously and get nighttime measurements Equatorial Aeronomy 43

44 CSR- Bistatic Mode (4) Nighttime capability (?) December 2003 Analog rxs., 100 kw tx March 2004 Digital rxs., 40 kw tx at least peak densities? Nighttime Daytime Nighttime Equatorial Aeronomy 44

45 (from Woodman [1997]) Equatorial Aeronomy 45

46 Antennas for Aperture Synthesis Imaging (Lots of Baselines!) 4 1/256 th s Tx on North and South quarters Module Hysell 64 th s Swartz, 03/11/7

47 Radar Imaging(1) ESF (from Hysell et al. [2004]) Equatorial Aeronomy 47

48 Radar Imaging (2) EEJ (from Chau and Hysell [2004]) Equatorial Aeronomy 48