Local high-temperature phenomena within magnetic clouds

作者：Jiemin WANG,Hengqiang FENG,Hongbo LI,Yan ZHAO

摘要：In this study,three methods were used to analyze 17 large-scale local high-temperature regions with durations exceeding 2 h within magnetic clouds(MCs)observed by advanced composition explorer from 1998 to 2008.Results show that five of these large-scale regions may have been caused by flare heating;seven of the regions may have been caused by nonuniform expansion when MCs propagated in the solar-terrestrial space;four large-scale high temperature regions may likely result from combined non-uniform expansion and flare heating;and only one large-scale local high-temperature region was not related to either flare heating nor non-uniform expansion.No evidence indicated that magnetic reconnection occurred or had occurred within the high-temperature regions.Based on our results,we infer that such local high-temperature phenomena within MCs are caused primarily as a result of flare heating and non-uniform expansion,either separately or jointly,and that magnetic reconnection plays only a minor role in the formation of high-temperature regions.

发文机构：Institute of Space Physics Henan Key Laboratory of Electromagnetic Transformation and Detection

关键词：MagneticcloudHigh-temperatureregionsFlareheatingNon-uniformexpansion

分类号： P18[天文地球—天文学]