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Munetoshi Tokumaru , Masayoshi Kojima, Ken ’ ichi Fujiki, Hiroaki Itoh, and Tomoya Iju

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).

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Munetoshi Tokumaru , Masayoshi Kojima, Ken ’ ichi Fujiki, Hiroaki Itoh, and Tomoya Iju

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  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 Sugadaira antenna • Measurements • Solar wind speed • Scintillation level (g-value)~ΔNe Kiso IPS Telescope (KIT) SWIFT Fuji IPS Telescope (FIT) Toyokawa antenna

  3. New IPS Antenna at Toyokawa SWIFT (Solar Wind Imaging FaciliTy) 41m(E-W) 106m (N-S) • Meridian Transit Obs. • Beam: 1 (Steerable in NS) • Frequency 327 MHz Effective Area: Ae～3382㎡×cosθ×η×D2(θ) η~90%、D(θ): directivity of dipole

  4. Receiver Housing

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

  6. All-Sky g-maps2008/11/04 Kiso Toyokawa

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

  8. 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)

  9. 1996(Solar Minimum) Solar wind speed maps Blue= fast Red = slow 2000 1991

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

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

  12. 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.

  13. UK/EISCAT Russia UCSD STEL India Mexico MWA Toyokawa IPS Workshop2007 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 IPS WL FR

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