1. Coronal and Heliospheric Modeling of the May 12, 1997 MURI Event MURI Project Review, NASA/GSFC, MD, August 5-6, 2003 Dusan Odstrcil University of Colorado/CIRES & NOAA/Space Environment Center, Boulder, CO

2. Solar Wind Parameters Large variations in plasma parameters between the Sun and Earth Different regions involve different processes and phenomena We distinguish between the coronal and heliospheric regions with an interface located in the super-critical flow region (usually 18-30 Rs)

3. Modeling of Heliospheric Events Heliospheric model (ENLIL, 3-D MHD solar wind) Coronal model (SAIC, semi-empirical) Halo-CME (SOHO/LASCO) Photospheric magnetic field (NSO Kitt Peak) Time-dependent boundary values (N, T, V, B) Source-surface maps at 30 Rs CME cone model (Zhao et al.) Geometrical and kinematical data

4. Global Solar and Coronal Observations Remote solar observations of the photospheric magnetic field Remote coronal observations of the white-light scattered on density structures

5. Ambient Solar Wind Models SAIC 3-D MHD steady state coronal model based on photospheric field maps [Linker, Mikic, Riley] CU/CIRES-NOAA/SEC 3-D solar wind model based on potential and current-sheet source surface empirical models [Arge, Mayer, Pizzo] UCB 3-D MHD steady state coronal model based on photospheric field maps [Ledvina, Luhmann]

6. CME Cone Model [ Zhao et al., 2001 ] Best fitting for May 12, 1997 halo CME latitude: N3.0 longitude: W1.0 angular width: 50 deg velocity:650 km/s at 24 R s (14:15 UT) acceleration: 18.5 m/s 2

7. Boundary Conditions Ambient Solar Wind + Plasma Cloud CASE - 1 CASE - 2

8. Evolution of Parameters at Earth Ambient Solar Wind + Plasma Cloud CASE - 1 CASE - 2

9. Latitudinal Distortion of ICME Shape ICME propagates into bi-modal solar wind

10. Radial Compression of ICME Structure Fast stream follows the ICME

11. Radial Compression of ICME Structure ICME propagates into the enhanced density of a streamer belt flow

12. Synthetic White-Light Imaging ICME transforms its appearance from a halo-like shell to a distorted one with two bright spots (see right panel) Larger time-interval between two images are needed to capture expanding interplanetary transients Total BrightnessRunning Difference

13. Appearance of Transient Density Structure IPS observations detect interplanetary transients that sometime show two enhanced spots instead of a halo ring [Tokumaru et al., 2003] MHD simulation shows a dynamic interaction between the ICME and ambient solar wind that: (1) forms an arc-like density structure; and (2) results in two brighter spots in synthetic images

14. Propagation of Energetic Particles IMF line connected to Earth by- passes the shock structure => Interplanetary CME-driven shock cannot generate energetic particles observed at Earth IMF line connected to Earth passes through the shock structure => Quasi-perpendicular shock can generate energetic particles under certain circumstances Early timeLater time

15. Energetic Particles & Radio Emission Important effect occurs away from the Sun-Earth line Enhanced shock interaction together with quasi- perpendicular propagation relative to IMF lines favors particle acceleration and generation of radio emission Global viewDetailed view

16. Near-Earth Observations Internal magnetic structure (flux rope) is not included Interplanetary magnetic field is distorted by: shock compression, field line draping around ejecta, and stretching in rarefaction region

17. Examples of Ongoing Work Analytic flux-rope models (Vandas)Event-driven coronal models (Ledvina) Graphical user-interface tools (Markel)Coupling with SEP, IPS, & SMEI (Jackson, Ledvina, Lee, Vandas)

18. Conclusions: Modeling of Interplanetary Events It is now possible to: - simulate ambient solar wind structure; - estimate arrival of shock and ejecta; - provide a global context. It is not yet possible to: - reproduce the internal magnetic structure of interplanetary CMEs (due to lack of coronal magnetic field observations). Next steps: - initialization from photospheric observations; - multi-point, multi-perspective advanced observations; - framework for modeling, visualization, and analysis; - validation studies.