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Upgrade of STEL Multi-Station Interplanetary Scintillation System and Recent Observations of the Solar Wind Munetoshi Tokumaru, Masayoshi Kojima, Ken ’

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Presentation on theme: "Upgrade of STEL Multi-Station Interplanetary Scintillation System and Recent Observations of the Solar Wind Munetoshi Tokumaru, Masayoshi Kojima, Ken ’"— Presentation transcript:

1 Upgrade of STEL Multi-Station Interplanetary Scintillation System and Recent Observations of the Solar Wind Munetoshi Tokumaru, Masayoshi Kojima, Ken ’ ichi Fujiki, Hiroaki Itoh, and Tomoya Iju (STEL, Japan). Given by Mario M. Bisi (CASS-UCSD) and Periasamy Manoharan (Ooty)

2 STEL 327-MHz Multi-Station IPS System SWIFT Kiso IPS Telescope (KIT) Fuji IPS Telescope (FIT) Sugadaira antenna Toyokawa antenna Measurements Solar wind speed Scintillation level (g-value)~ΔNe

3 41m(E-W) 106m (N-S) New IPS Antenna at Toyokawa SWIFT (Solar Wind Imaging FaciliTy) Meridian Transit Obs. Beam: 1 (Steerable in NS) Frequency 327 MHz Effective Area: A e ~ 3382 ㎡ ×cosθ×η×D 2 (θ) η~90% 、 D(θ): directivity of dipole

4

5 Receiver Housing

6 Variations of Scintillation Level and g-value for Source B1730-13 in 2008 IPS level g-value Time Radial Distance The g-value represents the relative variation of scintillation level; i.e. solar wind density fluctuations ΔN e (Gapper et al., 1982).

7 All-Sky g-maps 2008/11/04 Toyokawa Kiso

8 Model Fitting Analysis of IPS Power Spectrum Speed=379km/s Axial Ratio=0.99 Spectral Index=3.17 Speed=499km/s Axial Ratio=0.51 Spectral Index=4.34 3C48 2009/4/63C49 2009/4/6

9 Further Development of Multi-Station IPS System  Upgrade of Fuji and Kiso IPS Telescopes  Dipoles, Antenna Driving System, Receiver Backend, PCs (FY2009-2010)  Receiver Frontend (FY2011; not funded yet)  This allows us to take correlation between Toyokawa and Fuji, Kiso to derive the solar wind speed Fuji IPS Telescope (FIT) Kiso IPS Telescope (KIT)

10 1991 2000 Solar wind speed maps Blue= fast Red = slow 1996(Solar Minimum)

11 Comparison of Solar Wind Speed Maps between CR 1910 and 2070 2008.5.13~6.9 1996.6.1~6.28 Fast winds exist over the poles and equator. Slow winds are in between them. i.e. Non- Dipolar Structure. The previous minimum data exhibit a Dipolar Structure.

12 Synoptic Carrington Solar Wind Speed Maps for 2008 (Cycle 23/24) and 1996 ( Cycle 22/23) 1.Equatorial fast wind 2.Rapid evolution of the large- scale structure 3.Larger latitude width of slow wind region

13 Summary  Upgrade Project of STEL Multi-Station IPS System  Development of a New IPS Antenna at Toyokawa (SWIFT), and Preliminary Observations  Improvement of Fuji and Kiso IPS Antennas  Recent STEL Observations  Peculiar Aspect of the Current Sunspot Minimum  Ref. Tokumaru et al., GRL, in press, 2009 (doi:10.1029/2009GL037461).  Continuous monitoring of the solar wind is needed.

14 Toyokawa IPS Workshop 2007 October 30-31  A Series of IPS workshops  San Diego, US (2004), Pushchino, Russina (2006)  Topics  IPS Observations and Space Weather Studies  Collaboration with Spacecraft Mission  Basic Sciences Using Heliospheric Sounding Measurements  IPS World Network and Common Database 22 participants from US, UK, Germany, India, Russia, Mexico, and Japan STEL MexicoIndia UCSD UK/EISCAT Russia MWA IPS WL FR


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