TY - JOUR

T1 - Particle precipitation during ICME-driven and CIR-driven geomagnetic storms

AU - Longden, N.

AU - Denton, Michael H.

AU - Honary, Farideh

N1 - Copyright (2008) American Geophysical Union. Further reproduction or electronic distribution is not permitted

PY - 2008/6/5

Y1 - 2008/6/5

N2 - Interplanetary coronal mass ejections (ICME) and corotating interaction regions (CIR) alter the parameters of the solar wind and interplanetary magnetic field (IMF) that affect conditions in the Earth's magnetosphere and particle precipitation in the auroral zone. We perform a superposed epoch study of the effects of ICME-dominated and CIR-dominated solar wind on particle precipitation during geomagnetic storms. We use data from a set of 38 CIR events and 33 ICME events. Particle precipitation is inferred from cosmic noise absorption (CNA) recorded by the riometer at Abisko. The electron flux intensity at geosynchronous orbit close to the location of the riometer is taken from the synchronous orbit particle analyzer (SOPA) onboard the Los Alamos National Laboratory (LANL) satellite LANL-01A. The results show that mean CNA is more intense during the main phase of ICME-driven storms. In contrast, mean CNA remains elevated for a much longer period during CIR-driven storms indicating prolonged periods of particle precipitation. Enhanced CNA over a sustained period of time is observed during CIR-driven storms that are categorized as only weak or moderate in terms of the response that they drive in the Dst index (Dst >−100 nT). This result indicates that events which may be considered geomagnetically ineffective have a significant effect on particle precipitation in the auroral zone. The elevated CNA observed during CIR-driven storms is accompanied by elevated electron flux intensity, measured at geosynchronous orbit, over all channels in the 50–500 keV range at all local times.

AB - Interplanetary coronal mass ejections (ICME) and corotating interaction regions (CIR) alter the parameters of the solar wind and interplanetary magnetic field (IMF) that affect conditions in the Earth's magnetosphere and particle precipitation in the auroral zone. We perform a superposed epoch study of the effects of ICME-dominated and CIR-dominated solar wind on particle precipitation during geomagnetic storms. We use data from a set of 38 CIR events and 33 ICME events. Particle precipitation is inferred from cosmic noise absorption (CNA) recorded by the riometer at Abisko. The electron flux intensity at geosynchronous orbit close to the location of the riometer is taken from the synchronous orbit particle analyzer (SOPA) onboard the Los Alamos National Laboratory (LANL) satellite LANL-01A. The results show that mean CNA is more intense during the main phase of ICME-driven storms. In contrast, mean CNA remains elevated for a much longer period during CIR-driven storms indicating prolonged periods of particle precipitation. Enhanced CNA over a sustained period of time is observed during CIR-driven storms that are categorized as only weak or moderate in terms of the response that they drive in the Dst index (Dst >−100 nT). This result indicates that events which may be considered geomagnetically ineffective have a significant effect on particle precipitation in the auroral zone. The elevated CNA observed during CIR-driven storms is accompanied by elevated electron flux intensity, measured at geosynchronous orbit, over all channels in the 50–500 keV range at all local times.

KW - riometer DCS-publications-id

KW - art-894

KW - DCS-publications-credits

KW - iono-fa

KW - DCS-publications-personnel-id

KW - 91

KW - 123

KW - 5

UR - http://www.scopus.com/inward/record.url?scp=50249129508&partnerID=8YFLogxK

U2 - 10.1029/2007JA012752

DO - 10.1029/2007JA012752

M3 - Journal article

VL - 113

SP - 1

EP - 12

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - A06205

ER -