Halo CME on 20040725 - SOHO/LASCO C3 Data

COMMENTS: If the disturbance in the IMF, which started on July 26 at 2230UT is associated with the halo CME on July 25th, then it seems that the CME speed was significantly underestimated. The height-time plot for this event shows a wide range of speeds and for the prediction we ususlly take speed measured at about 20 solar radii (~700km/s). Now that we know the travel time, the initial speed can be estimated according to the Gopalswamy et al., 2000, GRL, 27 plot (Fig 3): for the travel time of about 34 hours the initial speed should be about 1300 km/s. Then the Bz is estimated to be between -20 ... -34 nT (about -25nT according to ACE data), while the Dst index should drop by 177 ... 244 nT (Dst decreased by ~170 nT from -32nT to -200nT).

1Numbers in red are estimates. Numbers in parenthesis (if any) are actual measured values
*These estimates should be compared to the observed 1 hour averaged ACE and Dst values

  • Real Time Dst from World Data Center for Geomagnetism, Kyoto
  • Predicted Dst from Nonlinear Dynamics and Space Physics group
  • Real Time ACE data
  • Today's Space Weather

    Full Disk Halpha Full Disk SOHO/MDI Full Disk SOHO/EIT195
    Active Region Halpha Active Region SOHO/MDI Active Region /EIT195
    Images are courtesy of Active Region Monitor

    Automaticaly Generated on Mon Jul 26 09:41:26 2004
    Please, send questions and comments to Vasyl Yurchyshyn