American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 813898 bytes)    Cited by

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, A07S05, doi:10.1029/2005JA011379, 2006

Geoeffectiveness of corotating interaction regions as measured by Dst index

M. V. Alves

Laboratório Associado de Plasma, Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


E. Echer

Divisão de Geofísica Espacial, Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


W. D. Gonzalez

Divisão de Geofísica Espacial, Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


Abstract

Corotating interaction regions (CIRs) are structures formed when high-speed solar wind streams overtake slow solar wind streams as they propagate outward. These structures produce regions of enhanced density and magnetic field strength in the solar wind near the ecliptic plane. In this paper, the geoeffectiveness of CIRs, as measured by the geomagnetic Dst index, is assessed during the solar wind observational period 1964–2003. A catalogue of CIRs is constructed by consulting high-speed plasma streams (HSPS) lists present in the literature and by analyzing solar wind parameters for each HSPS event. The geoeffectiveness of CIRs is analyzed by determining the number of intense (Dst ≤ −100 nT), moderate (−100 < Dst ≤ −50 nT), or weak (−50 < Dst ≤ −30 nT) magnetic storms that followed each CIR event. Statistical distributions of CIR parameters (maximum solar wind speed, maximum convection electric field, southward magnetic field peak) and geoeffectiveness (Dst peak) are obtained. Correlation analyses of Dst index with various solar wind parameters are presented. A comparison with the geoeffectiveness of other interplanetary structures such as shocks, magnetic clouds, and sector boundaries is performed. Our results show that 33% of CIRs are followed by moderate/intense magnetic activity (Dst < −50 nT), i.e., approximately one third of the CIR events observed near Earth are geoeffective.

Received 23 August 2005; accepted 28 November 2005; published 12 May 2006.

Keywords: solar wind plasma; corotating streams; solar wind/magnetosphere interactions; magnetic storms.

Index Terms: 2102 Interplanetary Physics: Corotating streams; 2134 Interplanetary Physics: Interplanetary magnetic fields; 2164 Interplanetary Physics: Solar wind plasma; 2101 Interplanetary Physics: Coronal mass ejections (7513); 2784 Magnetospheric Physics: Solar wind/magnetosphere interactions.

Read Full Article (file size: 813898 bytes)    Cited by

Citation: Alves, M. V., E. Echer, and W. D. Gonzalez (2006), Geoeffectiveness of corotating interaction regions as measured by Dst index, J. Geophys. Res., 111, A07S05, doi:10.1029/2005JA011379.