The Relation between Soft X-ray Ejections and Hard X-ray Emission on November 24 Flare

H. Takasaki, T. Morimoto, A. Asai, J. Kiyohara, and K. Shibata Kwasan and Hida observatories, Kyoto University, Japan

takasaki@kwasan.kyoto-u.ac.jp

1. Introduction

3. Result

4. Discussions and Summary

(Ohyama and Shibata 1998)(Ohyama and Shibata 1998)

②

⑦⑥

④

③

①⑤

0.50

(0.35)

0.64

(0.46)

0.58

(0.41)

0.82

(0.59)

1.4

(1.0)

1.1

(0.79)

0.86

(0.61)

Energy(*1028erg)

10.21.50.821.14.53.22.6Mass

(*109 g)

450.5956.51186.71227.6785.0816.2814.4Average velocity

(km/sec)

⑦⑥⑤④③②①

150

(0.1)

580

(0.39)

600

(0.4)

950

(0.63)1500

(1.0)

1300

(0.87)

1000

(0.67)

HXR

(CT/S/sc)

Recently, the so-called CSHKP model is the most commonly quoted as the magnetic reconnection model for solar flares. In this models, the accelerated particles started from reconnection region precipitate into the chromosphere along the magnetic field line and produce dominant hard X-ray (HXR) emission by bremsstrahlung on the chromospheric materials. On the other hands, the coronal plasma materials called soft X-ray (SXR) plasmoid are often ejected in upper direction from reconnection region.

Ohyama & Shibata (1998) reported that plasmoid ejections are strongly accelerated at impulsive phase of solar flare when the hard X-ray is impulsively emitted.

2. Observation

We examine the X2.3 flare which occurred on 2000 Nov. 24 and found that multiple SXR plasmoids are ejected one after another like upper figure, while the HXR source dominantly appeared as double footpoint sources which is located above flare ribbon (left figure).

In the HXR time profile, we can clearly see many intermittent and bursty emissions. So, we examine the relationship between these HXR bursts and ejected SXR plasmoids.

We can clearly see the SEVEN plasmoids in this flare. We estimate the time, location, acceleration, and velocity for each plasmoid in order to examined temporal relation between HXR emission and SXR plasmoids. Assuming that the starting location of each ejected plasmoid is the central position of flare two ribbons, each plasmoid is temporally well-correspond to each intermittent and unsteady peak of HXR emission, respectively.

Time slice image

(i)

(iii)

(iv)

(ii)

The thin current sheet by the tearing instability becomes unstable again because of the secondary tearing instability. As a results, the many small plasmoids are created one after another and ejected along the current sheet when the magnetic reconnection occurred. (Tanuma et al. 2001)

plasmoid ejection

downflows

Asai et al. (2004) found that the times when the downflow motions start to be seen correspond to the times when bursts of nonthermal emissions in hard X-rays are emitted. This result implies that the downflow motions occurred when strong magnetic energy was released and that they are, or are correlated with, reconnection outflows.

Recently, some researchers reported the production and the behavior of magnetic island in the current sheet.

Our results suggest that the magnetic reconnection occurs very unsteadily in solar flare. Furthermore, our results imply that the plasmoid ejection plays the key role in triggered the fast magnetic reconnection.

Our main results are below ;

(i) Multiple ejections is well correspond to HXR intermittent peaks, respectively.

(ii) The number of high energy particles which produce the HXR emission has positive relation to the kinetic energy of SXR plasmoid ejections.

Note: yellow values are normalized by maximum value (3rd plasmoid).Yohkoh/HXT M2-band

The number of high energy particles which produce the HXR emission has positive relation to the kinetic energy of SXR plasmoid ejection at each intermittent burst.

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系列 1

Energy [1028erg]

HXR [CT/s/SC]