ROCSAT-1 Satellite Observations of Magnetic Anomaly Density Structures During the Great Magnetic Storm of July 15-16, 2000

Abstract

Large scale ion density structures were observed by ROCSA T-1 at 630 km altitude over the South Atlantic anomaly (SAA) region during the great magnetic storm of July 15-16, 2000. The observed density structures were confined within 30° in longitude east of the SAA, and co-rotated with the SAA for over 8 hours. The magnetic anomaly density structures (MADS)

On a possible relationship between density depletions in the SAA region and storm-enhanced densities in the conjugate hemisphere

“…1. During this magnetic superstorm, ROCSAT-1 detected a large ion density depletion at low latitudes (o351S) in the nighttime ionosphere after magnetic storm activity reached its peak intensity, lasting 8 h through the end of the magnetic storm (Lin et al, 2001). The bottom panel of Fig.…”

“…Lin et al (2001) demonstrated that these large-scale density dropouts corotated with the South Atlantic anomaly (SAA) and were adjacent to regions of density enhancement, forming a magnetic anomaly density structure (MADS). While the large-scale density dropouts were detected in the southern hemisphere, ground-based global positioning satellite (GPS) total electron content (TEC) measurements have indicated large-scale storm-enhanced density (SED) in the northern hemisphere during magnetic superstorms (Foster et al, 2002;Kelley et al, 2004;Yin et al, 2004).…”

“…Low-earth orbiting satellites have detected largescale ion density dropouts with a spatial width greater than 800 km in the low-latitude ionosphere during several magnetic superstorms (Greenspan et al, 1991;Basu et al, 2001;Lin et al, 2001, Lee et al, 2002Su et al, 2002;Lin and Yeh, 2005). Lin et al (2001) demonstrated that these large-scale density dropouts corotated with the South Atlantic anomaly (SAA) and were adjacent to regions of density enhancement, forming a magnetic anomaly density structure (MADS).…”

“…The bottom panel of Fig. 1 taken from Lin et al (2001) is a composite overview of ion density structures measured by the ROCSAT-1 ion trap sensor for this event. Large density depletions and enhancements (MADS) were detected from 3001 to 3401E geographic longitude, east of the center of the SAA.…”

Advanced Ionospheric Probe scientific mission onboard FORMOSAT-5 satellite

“…It is interesting that similar observations of large density depletion events were again observed during the 6 -7 April 2000 and the 15 -16 July 2000 magnetic storms by ROCSAT-1 satellite, at 600 km altitude traversing the magnetic flux tube in the east-west direction. The 15 -16 July events were reported to correlate with the SAA region (Lin et al 2001). The large density dropout was further classified by Su et al (2002) in two groups of ESF plasma irregularities that occurred in either side of the midnight meridian during the storm recovery phase.…”