Paper#: 68
Poster #:
Session Name: Workshop 1B: High Latitude Processes
Room: West Ballroom
Day: Monday
Time: 3:00-3:25 p.m.
Abstract Title: Investigation of Optical Signatures of the Substorm Growth Phase
PresentSurname: Meng, C.I.
All Authors: C.I. Meng
Abstract : Since first introduced three decades ago, the substorm growth phase has been one of the central issues in magnetospheric substorm physics. The growth phase of substorm may be loosely defined as a time period in which energy is extracted from the solar wind and stored in the magnetotail before the substorm onset. However, known signatures that can be related to the growth phase are, not always nor uniquely, observed leading to a question whether or not a growth phase for substorm is necessary and observable. In this report, we will address this question by examining global auroral images acquired from the Polar ultraviolet imager (UVI) and comparing results with ground-based meridian scanning photometer (MSP) data. The main goal is to find identifiable auroral features of global aspects for substorm growth phase. Specifically, the well-known growth phase optical signature, equatorward expansion of the oval, primarily reported based on MSP observations, will be thoroughly investigated. Our preliminary results, based on a comparison of a number of isolated substorm events observed by MSP and by Polar UVI, strongly indicate that identification of the substorm growth phase based on the spatially limited MSP technique can sometimes be misleading. Detailed results will be presented and discussed.