太阳活动区上空两个微波超快速吸收现象的观测与分析

OBSERVATION AND ANALYSIS OF TWO MICROWAVE ULTRA-FAST ABSORPTION PHENOMENA ABOVE SOLAR ACTIVE REGIONS

1987年5月19日世界05h50m17-05k50m25s和1986年6月29日世界时07h38m50s-07h38m58s两个罕见的微波超快速吸收现象分别出现在太阳活动区NOAA／USAF4808和5060上空的3.67GHz和4.00GHz大气层中.当云南天文台高时间分辨率射电望远镜观测到这种吸收现象时，在2.84GHz和1.42GHz大气层中出现的是尖峰辐射，两次超快速吸收现象的显著观测特征是：（1）吸收期的持续时间为20—25ms；（2）吸收的流量范围在17-215s．f.u．；（3）超快速吸收形态与快速吸收形态基本相似；（4）超快速吸收现象均叠加在秒级爆发上，秒级爆发分别为44NS和46C型；（5）相伴随的Ha耀斑分别为SF级和3B级．

Two rare phenomena of microwave ultra-fast absorption occurred at 3.67GHz and 4.00GHz in the atmospheric layers above solar achve regions of NOAA / USAF 4808 and 5060 in the interval 05h50m17s-05h50m25s UT on May 19, 1987 and 07h38m50s-07h38m58s UT on June 29, 1988, respechvely. These absorphon phenomena were observed with the radio telescopes of high temporal resoluhon at Yunnan Observatory. Spike endssions appeared at b0th 2.84GHz and 1.42GHz. The notable observahonal characterishcs of the two absorphon phenomena are as followst (1) The durations are from 20 to 25ms. (2) The ranges of abs0rphon flux are from 17 to 215s.fu. (3) the forms of fast and ultrafast absorphon phenomena are mainly similar. (4) Both ultra-fast absorption phenomena were superposed on the secondary bursts which are of the types 44NS and 46C, respectively. (5) They were accompanied by Ha flares of imprtances SF and 3b, respectively.