Coronal mass ejections and other extreme characteristics of the 2003 October–November solar eruptions

Abstract

[1] Fast coronal mass ejections (CMEs), X-class flares, solar energetic particle (SEP) events, and interplanetary shocks were abundantly observed during the episode of intense solar activity in late October and early November 2003. Most of the 80 CMEs originated from three active regions (NOAA ARs 484, 486, and 488). We compare the statistical properties of these CMEs with those of the general population of CMEs observed during cycle 23. We find that (1) the 2003 October-November CMEs were fast and wide on the average and hence were very energetic, (2) nearly 20 percent of the ultrafast CMEs (speed !2000 km s À1 ) of cycle 23 occurred during the October-November interval, including the fastest CME of the study period ($2700 km s À1 on 4 November 2003 at 1954 UT), (3) the rate of full-halo CMEs was nearly four times the average rate during cycle 23, (4) at least sixteen shocks were observed near the Sun, while eight of them were intercepted by spacecraft along the Sun-Earth line, (5) the CMEs were highly geoeffective: the resulting geomagnetic storms were among the most intense of cycle 23, (6) the CMEs were associated with very large SEP events, including the largest event of cycle 23. These extreme properties were commensurate with the size and energy of the associated active regions. This study suggests that the speed of CMEs may not be much higher than $3000 km s À1 , consistent with the free energy available in active regions. An important practical implication of such a speed limit is that the Sun-Earth travel times of CME-driven shocks may not be less than $0.5 day. Two of the shocks arrived at Earth in <24 hours, the first events in $30 years and only the 14th and 15th documented cases of such events since 1859.

Global Properties of Solar Flares

“…Fig. 20 Correlation of CME kinetic energy with GOES peak flux, based on the Halloween flare data given by Gopalswamy et al (2005) …”

Interacting CMEs and their associated flare and SEP activities

“…Interacting CMEs associated with Type II radio burst cause solar energetic particles as listed by Gopalswamy et al(2001b). Type II radio burst occurring at all wavelengths from metric to kilometric are associated with most energetic CMEs (Gopalswamy et al,2005). Long wavelength radio emission in decameter-hectometric (DH) wavelength from 1kHz to 14 MHz frequency range is important to understand the effects of CME in the outer corona and in the IP medium.…”

Underlying scaling relationships between solar activity and geomagnetic activity revealed by multifractal analyses

“…Solar active regions produce CMEs with near-Sun speeds around or excess of 900 km/s [e.g., Sheeley et al, 1999] as well as solar flares. Gopalswamy et al [2005] reported that part of the most energetic (X-class) flares are associated with fast CMEs. Hence, large flares (X-class) correlate to the fast CMEs, which cause the large geomagnetic storms.…”

“…Solar active regions can produce CMEs with near-Sun speeds in excess of 900 km/s [e.g., Sheeley et al, 1999] and solar flares. Gopalswamy et al [2005] reported that part of the most energetic (X-class) flares are accompanied by fast CMEs. Based on the statistics from 103 events, Howard and Tappin [2005] found that approximately 40% of the X or M class flares were associated with observed shocks in the solar wind at Earth.…”