【摘要】 据X射线、可见光（H_α及白光）和射电波段的观测资料,对1981年4月1日太阳大爆发（4N/X2.3）作了综合描述。分析指出:大黑子光桥的消减（作为磁通量变化或磁流浮现的一种形式）、黑子的隐现及小黑子的运动可能是促成这次爆发的直接原因;耀斑前暗条弯曲程度的增加显示了磁场挤压或剪切程度的增强;爆发的软、硬X射线源和微波源位于磁拱形结构的顶部;能量≥20keV的非热电子在第一个爆发峰中提供的能量约为4.3×10³¹erg。更多还原

【Abstract】 A number of major flares were observed and studied since 19th solar cycle, but important questions such as the relation between sources in different wave ranges are still open, A combined study of space and ground-based observations in various wave ranges of a big burst might produce some useful results for resolving these problems. The 4N/X2.3 flare of April 1, 1981, one of the most intense events occurring during the cycle 21, is investigated in this paper by means of the relevant Hα, white light. X-ray (Hinotori satellite) data and radio data mainly supplied by Culgoord and Learm-onth Observatories.The disappearence or contraction of the bright bridges in Sunspots A and C, the growth of Sunspot F, and in particular, the movement of minor Sunspots E1 and E2 (see Figs. 2, 3) might be the direct cause of the occurence of the great flare studied. The disappearence of bright bridges might be one kind of EMF.The consistence of peaks in X-ray and microwave emission (Fig. 6), the relation between 35 GHz and X-ray sources as pointed by Kawabata et al. (1982), and the work by Takakura et al. (1984) show observational evidence for that the soft and hard X-ray emission and microwave emission have a common source of the event.A superimposed map of the hard X-ray (13-29 keV) source. Hα ribbon, and potential field (Fig. 9) shows that the main part of the hard X-ray source locates at the ridge of the close magnetic arcade above the north-west part of the Hα flare, and has a height of 2×10 km above the photosphere.Taking the flux of the first peak (0136 UT) in microwave as 2000 sfu and the width of the pulse as 3 minutes, the energy supplied by non-thermal electrons with energy≥20 keV during the first peak is estimated as 4.3×1031 ergs according to the figure given by Hudson et al. (1978) for a thick target.The authors are deeply indebted to Dr. G. J, Nelson at Culgoora Observatory for valuable help and supplying data, and thank the staff of Learmonth Observatory for relevant data.更多还原