May 11-13, 1993

Fig. 1. Appearance of the transequatorial microwave chain.

(a) - Only some blobs and small chains are present near the complex of ARs 7496 and 7500 located westward from the transequatorial coronal hole observed with the Yohkoh/SXT (d).

(b)-(c) - After the C2.1 soft X-ray LDE event , peaked on May 11 at 21:52 UT in AR 7500, a transequatorial microwave chain 1-2-3 is being developed (b) along the narrow part of the coronal hole (e,f). The chain seems to go also from AR 7496 to the west limb (point 5) and then to AR 7502, as well as from point 3 through AR 7503 to point 4 near the south-east limb (see Figure 2). This chain is clearly seen also on May 13 (c).

Fig. 2. Evolution of the microwave chains of May 11-12, 1993.

Top - The GOES-7 soft X-ray plot with the C2.1 LDE event in the complex of ARs 7496 and 7500.

(a)-(d) - The chain 1-2-3-AR 7503-4 is kept. An additional part of the chain is being developed from point 1a in the west and south directions to point 5 and AR 7502 (a,b). Some hours later (c,d), a new diffuse fragments of the chain, going directly from the south-west (5) to the south-east (4) limbs through points 2 and 3 can be distinguished.

 A movie showing evolution of the microwave chains after the LDE event of May 11-12, 1993

May 14-15, 1993

Fig. 3. Further development of the transequatorial microwave chain of May 14-15, 1993.

(a)-(d) - On 14 and 15 May, the fragments of the transequatorial microwave chains 2-3-4 in (a) and (b) continue to exist and to rotate coinciding with the tranequatorial coronal hole 1-2 in (c,d). On 15 May, after the 2B/M4.4 LDE event peaked on 14 May at 22:53 UT near AR 7500, the microwave chain is enhanced and developed again to the 1-2-3-4-5 configuration (b). Strong evolution, apparently associated with the LDE event, takes place in this case also similar to the 11-12 May event (the corresponding Figure will be presented some later).

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Last update: 2 April 1999