【作者】 肖池阶； 梁浩明； 李青晟； 周桂萍； 濮祖荫； 王红刚； 王晓钢；

【机构】 北京大学核物理与核技术国家重点实验室； 北京大学物理学院； 中国科学院国家天文台； 北京大学地球与空间学院；

【摘要】 Considering coronal mass ejection (CME) triggering models at present, the distributions of Alfvén waves in flux rope are different from model to model and, thus, examining those distributions in interplanetary coronal mass ejection (ICME) is effective way to connect ICME observations with those theoretical models. However, previous observations of Alfvénic fluctuations recorded in ICMEs were rare and only from 0.3 to 0.68 AU, which is usually explained as rapid dissipation of those remnant waves. Here we present an observation of Alfvén waves in a magnetic cloud (MC) in an ICME near 1 AU detected in situ by WIND during the period of February 17-20, 2011. The ICME was generated by a CME accompanied with the first X-class flare in the 24th solar cycle. The Power Spectral Densities of magnetic fluctuation in the MC, compared with those in ambient solar wind, show similar slopes but more anisotropic, which gives a case for the research of Alfvén wave turbulence with much smaller relative fluctuation amplitude of magnetic field than solar wind. The results will be helpful for studies of CME theories and ICME thermodynamics.更多还原

【Abstract】 Considering coronal mass ejection (CME) triggering models at present, the distributions of Alfvén waves in flux rope are different from model to model and, thus, examining those distributions in interplanetary coronal mass ejection (ICME) is effective way to connect ICME observations with those theoretical models. However, previous observations of Alfvénic fluctuations recorded in ICMEs were rare and only from 0.3 to 0.68 AU, which is usually explained as rapid dissipation of those remnant waves. Here we present an observation of Alfvén waves in a magnetic cloud (MC) in an ICME near 1 AU detected in situ by WIND during the period of February 17-20, 2011. The ICME was generated by a CME accompanied with the first X-class flare in the 24th solar cycle. The Power Spectral Densities of magnetic fluctuation in the MC, compared with those in ambient solar wind, show similar slopes but more anisotropic, which gives a case for the research of Alfvén wave turbulence with much smaller relative fluctuation amplitude of magnetic field than solar wind. The results will be helpful for studies of CME theories and ICME thermodynamics.更多还原