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IPS tomography IPS-MHD tomography

IPS tomography IPS-MHD tomography. However because of the line-of-sight integration effect of IPS, solar wind had to be studied with blurred images. In order to deconvolve the line-of-sight integration effect, Computer Assisted Tomographic (CAT) method was developed.

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IPS tomography IPS-MHD tomography

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  1. IPS tomographyIPS-MHD tomography

  2. However because of the line-of-sight integration effect of IPS, solar wind had to be studied with blurred images. In order to deconvolve the line-of-sight integration effect, Computer Assisted Tomographic (CAT) method was developed. Since Hewish et al. reported the discovery of the interplanetary scintillation (IPS) phenomena in 1964, the IPS method has been one of the few devices which can observe solar wind in three-dimensional space. Although the solar wind is extended radio scattering medium, old IPS analysis method assumed that the IPS observes the solar wind at a P-point where radio scattering is mostly weighted.

  3. EISCAT900 MHｚ1420 MHzLong base line 90 km

  4. Baseline length189 km Fresnel radius 90km After Breen et al., 1996

  5. Baseline length239 km Fresnel radius 90km After Breen et al., 1996

  6. ★ Sun High-speed SW Low-speed SW Earth

  7. Cross correlation 0 Lag time Long base line observation Resolve into fast and slow winds

  8. Since the baselines of STELab system are as short as Fresnel radius, STELab cannot resolve solar wind structure. However ….. STELab 327MHz RF=150 km base line =100km EISCAT 930MHz RF= 90km base line = 380 km

  9. Both solar rotation and solar wind outward motion provide us a large number of lines of sight, with which we can obtain perspective views of three dimensional solar wind structures. Using these large number of lines of sight, we can apply Computer Assisted Tomography for IPS analysis. This technique can retrieve not only unbiased solar wind parameters but also provides high spatial resolution.

  10. SW Born 近似 In conditions of weak scattering, the IPS observations can be mathematically represented using the Born approximation in which the observed diffraction pattern is regarded as a weighted sum of contributions from each thin scattering layer perpendicular to the line of sight.

  11. Corotating tomography • Time sequence tomography • Two-spheres tomography • MHD-IPS tomography • Time-dependent tomography

  12. Corotating tomography • Synoptic map of one rotation • Stable solar wind structure

  13. Corotating tomography longitude

  14. Corotating tomography CT Analysis

  15. Time sequence tomography • Continuous synoptic map through a year • Metastable solar wind

  16. Time sequence tomography

  17. Time sequence tomography Comparison of Ulysses and IPS Observations 1995 Red: IPS Black: Ulysses 2001

  18. Two-spheres tomography • R dependence of SW structure

  19. 0.3－0.9 AU 80o 50o 50o 80o 0.1－0.3 AU

  20. 80o 50o 50o 80o

  21. 14 data sets 14 data sets

  22. MHD-IPS tomography • IPS observations are used as outer boundary conditions. • Not only V and N but also T and B are obtained. • Stream-stream interaction is considered. • The analysis can be made beyond 1 AU even to • heliospheric boundary.

  23. Time-dependent MHD simulation from 5 to 900AU by HaruichiWashimi @ CSPAR, Alabama Univ. IPS-MHD CAT from SS to 5AU by Keiji Hayashi @ Stanford Univ. IPS CAT from SS to 1AU 1AU 5AU

  24. MHD-IPS CAT Simulation is started from the distance where the SW gets a final cruising velocity such as R>10 Rs. Inner boundary conditions T from an empirical relation with V, N from an empirical relation with V, B from observation and potential field model, V is determined by MHD-IPS CAT. Outer boundary condition IPS observations

  25. Advantages for MHD simulation to collaborate with IPS. • Simulation can starts from distance where SW acceleration is almost completed. • Simulation can use IPS observations as outer boundary conditions.

  26. MHD simulation Hayashi et al.

  27. N V 0.25AU １AU Hayashi et al.

  28. ３D MHD Tomography

  29. IPS-MHD Tomography Spacecraft observations

  30. MHD-IPS CAT can obtain solar wind structure at any distance form the sun. Comparison with Ulysses observations in1995～1998 B T N V UlyssesＩＰＳ－MHD Hayashi et al.

  31. Time-Dependent MHD Simulation By Hayashi and Washimi • Period: 2001.1.1-2009.12.31 • Simulation Box: 5-900AU • Inner boundary: IPS-MHD tomography map at 5AU by Hayashi • outer boundary（LISM)： • Np=0.061/cc • NH=0.176/cc • T=6300 K • BLISM=4.8μG(distance of TS crossed by V1) • BLISM＝(225o,45o) in ecliptic coordinate • VLISM=26.3km/s • Solar Wind: • Density variationof SW: 5.0/cc (2005)  3.5/cc (2008) • linear interpolation • Mutual charge exchange (PUI)

  32. Global Picture Of Heliosphere km/s 2009/12/31 Turbulent flow LISM BLIS boundary of Flow

  33. Time-dependent tomography • ICME

  34. Weighting = IPS weighting x estimation error x angular distance

  35. V LOS Sun V fast fast slow slow Longitude

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