Direct observations of blob deformation during a substorm

作者：Ishida T^*; Ogawa Y; Kadokura A; Hosokawa K; Otsuka Y

来源：Annales Geophysicae, 2015, 33(5): 525-530.

DOI：10.5194/angeocom-33-525-2015

• Ionosphere
• ionospheric irregularities

Ionospheric blobs are localized plasma density enhancements, which are mainly produced by the transportation process of plasma. To understand the deformation process of a blob, observations of plasma parameters with good spatial-temporal resolution are desirable. Thus, we conducted the European Incoherent Scatter radar observations with high-speed meridional scans (60-80 s) during October and December 2013, and observed the temporal evolution of a blob during a substorm on 4 December 2013. This paper is the first report of direct observations of blob deformation during a substorm. The blob deformation arose from an enhanced plasma flow shear during the substorm expansion phase, and then the blob split into two smaller-scale blobs, whose scale sizes were more than similar to 100 km in latitude. Our analysis indicates that the Kelvin-Helmholtz instability and dissociative recombination could have deformed the blob structure.

• 出版日期2015
• 单位中国极地研究中心