Magnetic reconnection at dayside high latitudes and across wide local time: multiple X-line formation and electron structure?

Prof. Malcolm W. Dunlop

时间：2013-07-30星期二下午3:00

Time：July 30, 2013，Tuesday, Pm 3:00

地点：四楼报告厅

abstract

Evidence exists for predominantly component driven X-line regions, independent of guide field conditions, and extending across a wide range of preferred, and often multiple, locations. Active sites of MR have also increased the theoretical understanding of the detailed structure within the ion diffusion region surrounding the magnetic X-line or null field, although direct measurements of this small region are still relatively rare. We first investigate repeated sampling of the ion diffusion region and associated null magnetic field of a high-latitude reconnection site by the four Cluster spacecraft flying in formation to interpret the plasma structures surrounding the X-line, which is located on initially closed field-lines and where the magnetic field orientations inside and outside the magnetopause are close to anti-parallel. The plasma populations confirm details of the ion and electron mixing, time history and acceleration through the current layer. We secondly investigate the plasma distributions near X-line structures for key conjunctions of the Cluster, THEMIS and TC-1 spacecraft around the magnetopause, showing the operation of MR at wide locations along the expected sub-solar merging line. The results are also consistent with the occurrence of reconnection activity, simultaneously across the sub-solar and flank magnetopause, linked to the (large-scale) extended configuration of the merging line. Other small scale spacecraft configurations have revealed substructure in MR regions and details of the 3-Dbehaviourin multiple X-line scenarios.

Prof. Malcolm W. Dunlop is space environment scientist at RAL and is Co-I on the magnetic field and energetic and thermal plasma instruments on the Cluster and Double-Star missions, with extensive experience, through Cluster, in the (inter-) calibration and processing of magnetic field data, and in the design of multi-spacecraft methods (such as providing electric current densities and magnetic topology). His work has been highlighted 8 times in the Cluster public forum. The multi-spacecraft techniques have been documented in two books, and Cluster science results have been reviewed in two further books, for which he has written key chapters. He has in excess of 300 papers and is the second leading Cluster author from annternationalcommunity of over 1200. He is a visiting Professor at Imperial College London, Warwick University, and NSSC in Beijing, and has recently been appointed as a '1000 plan' foreign expert in China. He has run a number of funded projects; currently for mission support to Swarm.