Title Decrease of auroral intensity associated with reversal of plasma convection in response to an interplanetary shock as observed over Zhongshan Station in Antarctica
Author Liu, J.J.; Hu, H.Q.; Han, D.S.; Araki, T.; Hu, Z.J.; Zhang, Q.H.; Yang, H.G.; Sato, N.; Yukimatu, A.S.; Ebihara, Y.
Author Affil Liu, J.J., State Ocean Administration, Polar Research Institute of China, Shanghai, China. Other: National Institute of Polar Research, Japan; Nagoya University, Japan
Source Journal of Geophysical Research, 116(A3), Citation A03210. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0148-0227
Publication Date 2011
Notes In English. 29 refs. Ant. Acc. No: 91647. GeoRef Acc. No: 310655
Index Terms convection; geomagnetism; Antarctica-- South Pole; Antarctica; atmosphere; aurora; auroral intensity; imagery; interplanetary shocks; ionosphere; magnetic field; plasma; solar wind; South Pole; Super Dual Auroral Radar Network; Zhongshan Station
Abstract We examined temporal variations of a dayside aurora and corresponding ionospheric plasma convection observed by an all-sky camera (ASC) and the Super Dual Auroral Radar Network (SuperDARN) over Zhongshan (ZHS), located at -74.5 in magnetic latitude (MLAT) in Antarctica, during a geomagnetic sudden commencement (SC) event that occurred on 27 May 2001. Simultaneous ASC observations at South Pole (SP, -74.3 MLAT) were also analyzed. During the SC time, ZHS and SP were located in the postnoon (1610 MLT) and prenoon (1100 MLT) sectors, respectively. Before the SC onset (1458UT), the ASC at ZHS observed an auroral arc with moderate intensity in the poleward direction of the field of view (FOV), and the SuperDARN radar detected sunward ionospheric plasma flow over ZHS. Just after the SC onset, the auroral intensity over ZHS decreased rapidly and the direction of the plasma flow was reversed to antisunward. Decrease of auroral intensity and reversal of the associated plasma convection in response to a sudden increase of the solar wind dynamic pressure at the early stage of a SC event has never been reported before. We suggest that these observational results were generated by a downward field-aligned current (FAC) and are consistent with a physical model of SC. The model predicts the appearance of a pair of FACs flowing downward (upward) in the postnoon (prenoon) sector at the very beginning of the SC, which is also supported by our observations. Consistence of the detailed observations with the model will be discussed in the paper, and we argue that here we present the first optical observational evidence supporting the validity of the model.
URL http://hdl.handle.net/10.1029/2010JA016156
Publication Type journal article
Record ID 66000019