1. Using Potential Field Models to Learn About CME Coronal Context and Consequences J.G. Luhmann and Yan Li (Space Sciences Lab, UCB) C.N. Arge (CIRES, U. of Colorado and NOAA-SEC) X-P. Zhao and Yang Liu (Stanford University) O.C. St.Cyr (NASA GSFC and CUA) Nathan Rich (NRL and Interferometrics Inc.)

2. Active region distributions can be simple or complex (synoptic maps from SOHOMDI of CR 1915-1917, 1934-1936, and 1960-1962)

3. The potential field source surface model reproduces the coronal holes and shows the helmet streamer belt and active region field connections for CR1915. (SOHO EIT map from NRL LASCO website)

4. The potential field source surface model reproduces the coronal holes and shows the helmet streamer belt and active region field connections for CR1936. (SOHO EIT map from NRL LASCO website)

5. 09/26/96 LASCO C2, SXT, and PFSS

6. 26 September 1996 Haol CME: “Model” and SOHO EIT/LASCO image

7. Halos may be secondary streamer cylinders produced as a transient phase (right panel from ISTP website at GSFC) (bottom: hypothetical backside view)

8. 05/12/98 LASCO C2, SXT, and PFSS

9. CR1936 PFSS Views During CMEs

10. What We’ve Learned For simple CMEs, PFSS models allow visualization of the surrounding corona.For simple CMEs, PFSS models allow visualization of the surrounding corona. Complex CMEs are more challenging, but the PFSS model still provides the helmet streamer belt context.Complex CMEs are more challenging, but the PFSS model still provides the helmet streamer belt context. It would be good to try some of the same boundary conditions in global MHD models.It would be good to try some of the same boundary conditions in global MHD models.