-Short Talk- The soft X-ray characteristics of solar flares, both with and without associated CMEs Kay H.R.M., Harra L.K., Matthews S.A., Culhane J.L., Green L.M., 2003, A&A, 400, 779 July 14, 2003, Yu Liu

Introduction Complex relationship between flares and CMEs is not clear: case studies, statistical studies SXR statistical investigation: a close relationship between temperature, emission measure, duration and peak intensity (Harrison 1995, Feldman et al. 1995, 1996, Aschwanden 1999, Veronig et al. 2002), however, they do not differentiate between flares with and without CMEs

Purpose of this work To investigate the relationship between flares and CMEs using a comparison of flare parameters. With data from: GOES SXR LASCO (range of 1.1-32 solar radii) EIT (dimming signatures of CME lower in the corona)

Flares selected (69 samples) Both with and without CMEs GOES Class B to X Duration >= 3min simple events were included long duration flares with minor events during the decay phase were not excluded unambiguous determination of whether or not there was an associated CME

Flare parameters 1.peak intensity 2.duration 3.peak temperature 4.emission measure 5.EIT wave peak intensity 1-8 Å 0.5-4 Å duration Fig. 1

Detection of a CME LASCO EIT (FeXII 195A, dimming) If insufficient EIT data available, then compare EIT images before and after the event to examine field opening. Only those appeared without no CME were included

Results Table 1. mean temperature and flare durations Table 2. Mean flare duration and peak temperature

Table 3. Upper and lower limits of SXR flare characteristics

Figure 2. peak intensity vs. duration (69 flares)

Figure 3. Peak temperature vs. peak emission measure

Figure 4. Peak temperature vs. peak intensity

Figure 5. Rise time vs decay time

Figure 6. Rise time vs peak temperature

Discussion: How to understand the differences between flares with and without CMEs For a given peak intensity, flares with CMEs appear to reach lower peak temperatures, suggesting CMEs play the role to remove some energy from the region, so less energy to heat the plasma For a given peak temperature, flares with CMEs have higher values for the peak emission measure , suggesting a longer time is required to heat the plasma to the give peak temperature No correlation between peak intensity and duration for flares with CMEs, while a clear correlation for those without CMEs, suggesting CMEs can affect the timescale for energy release and cooling within the flares

Conclusion Clear correlation between peak intensity and duration for flares without CMEs Same correlation between peak temperature and peak emission measure for these two classes of flares No difference relationship between rise and decay time No relationship between the flare rise time and the peak temperature, suggesting… EIT waves have no correlation between those parameters

Further work To make more complete comparison, we should base on more samples and more wavelengths observations We will study the HXR properties and non-thermal velocities, using data from Yohkoh We will make detailed analysis of EIT and TRACE images, because magnetic field morphology may play an important role for a CME occurrence