One of the biggest magnetostorms in the solar cycle 23 occurred on March 31, 2001. Several imagers on IMAGE qualitatively show the effects of plasmapause erosion. In this study, we show the first, quantitative measurements of the depletion and refilling during the storm. The plasma density observations were made by the radio plasma imager which based on the resonant frequency of echoes and the time delays of the echoes remotely measures the density distribution along the magnetic field from one hemisphere to the other. We first derive the density distribution as function of radial distance and latitude before the storm from quiet times. We then compare the equatorial densities measured during and after the storm with those for the quiet time. The plasmapause was at L=4 before the storm. During and after the storm, the densities within (beyond) L=2.3 remain similar to (are substantially reduced from) that of quiet time, indicating that the plasmapause moved to as close as L=2.3 to the earth during the storm. Flux tubes between L=2.3 and L=4 underwent a depletion process during the storm. While the density near the ionosphere remained similar, the equatorial density dropped to as low as 30% of the quiet time value. After the storm, these emptied flux tubes started refilling. The refilling time lasted less than 28 hours.
AGU Spring Meeting Abstracts
- Pub Date:
- May 2002
- 2730 Magnetosphere: inner;
- 2768 Plasmasphere;
- 2784 Solar wind/magnetosphere interactions;
- 2794 Instruments and techniques