1. Line Profile Characteristics of Solar Explosive Event Bursts Z. Ning et al 2004 A&A 419,1141 Speaker: Jinping Dun

2. 1. Introduction Explosive Event is a small-scale, short-lifetime phenomenon in the transition region of quiet Sun. Main Characteristics Broaden Line Profile T ~ 10 5 K ( i.e. SiIV 1393 Å) V~100km/s Size ~ 2” Lifetime ~ 1min Physical Model Plasma Jets Produced by Magnetic Reconnection

3. 2. Observations and Data Reduction (i) MDI Magnetogram The area rastered by SUMER and locations of explosive events

4. 2. Observations and Data Reduction (ii) SiIV 1393 Å Spectrum Slit ~ 1” x120” Step ~ 6 Interval~ 1.13” Exposure Time ~5s

5. 3. Examples and Results (i) Time Variation of Integrated Intensity

6. 3. Examples and Results (ii) Repetition of Explosive Events

7. 3. Examples and Results (iii) 2D Time Evolution of 5 Groups of Events The black dashed line boxes surround events with obvious red-blue wing spatial offset. (Evidence of reconnection jets, Innes et al.,1997, Nature,386,811)

8. 3. Examples and Results (iv) The Magnetic Field Emergence (white) and Cancellation (black)

9. 4. Discussion 2D Structure Evolution of Explosive Events Repetition of Explosive Events Magnetic reconnection could be triggered by 3~5 min oscillation waves in the chromospheric and transition region.

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11. Profile of Explosive Event (i) Wavelength Velocity Along Line-of-sight V=0 V>0(red-shift)V<0(blue-Shift) Explosive Event

12. Profile of Explosive Event (ii) Ni 1393.33 SiIV 1393.78

13. three components: stationary and two high-speed (along line-of-sight) sources. (Chae et al.1998,ApJ,497,L109) stationary component blue-shift component red-shift components Profile of Explosive Event (iii)