TY - JOUR

T1 - Characteristics of pseudobreakups and substorms observed in the ionosphere, at the geosynchronous orbit, and in the midtail

AU - Aikio, AT

AU - Sergeev, VA

AU - Shukhtina, MA

AU - Vagina, LI

AU - Angelopoulos, V.

AU - Reeves, GD

PY - 1999/6/1

Y1 - 1999/6/1

N2 - We present a comprehensive study of a sequence of two substorms and multiple pseudobreakups using optical, magnetic and incoherent scatter radar measurements, energetic particles from two geosynchronous satellites and particle and field data from the Geotail spacecraft located at X-gsm similar to -86 R-E. Following conventional nomenclature, we classified as pseudobreakups those auroral breakups which did not exhibit significant poleward expansion (<2 degrees magnetic latitude). Auroral intensifications following substorm breakups were also observed, and were classified separately. Pseudobreakups were found not to differ from substorm breakups in longitudinal extent (from 1.3 to 6.1 hours of magnetic local time), or in duration (from 5 to 16 minutes). In general, the ionospheric currents producing ground magnetic disturbances were more intense during substorms than pseudobreakups, We found that pseudobreakups are;associated with the same magnetospheric processes as substorm breakups which involve current wedge formation, midlatitude magnetic Pi2 pulsations and energetic particle injections at the geosynchronous altitude. Moreover, pseudobreakups are associated with magnetic reconnection in the near-Earth region, evidenced by the typical subsequent detection of a plasmoid at Geotail. This implies that the magnetotail volume influenced by a pseudobreakup is quite large in radial distance. We conclude that there is no definitive qualitative distinction between pseudobreakups and substorms but there is a continuum of states between the smell pseudobreakups and large substorms.

AB - We present a comprehensive study of a sequence of two substorms and multiple pseudobreakups using optical, magnetic and incoherent scatter radar measurements, energetic particles from two geosynchronous satellites and particle and field data from the Geotail spacecraft located at X-gsm similar to -86 R-E. Following conventional nomenclature, we classified as pseudobreakups those auroral breakups which did not exhibit significant poleward expansion (<2 degrees magnetic latitude). Auroral intensifications following substorm breakups were also observed, and were classified separately. Pseudobreakups were found not to differ from substorm breakups in longitudinal extent (from 1.3 to 6.1 hours of magnetic local time), or in duration (from 5 to 16 minutes). In general, the ionospheric currents producing ground magnetic disturbances were more intense during substorms than pseudobreakups, We found that pseudobreakups are;associated with the same magnetospheric processes as substorm breakups which involve current wedge formation, midlatitude magnetic Pi2 pulsations and energetic particle injections at the geosynchronous altitude. Moreover, pseudobreakups are associated with magnetic reconnection in the near-Earth region, evidenced by the typical subsequent detection of a plasmoid at Geotail. This implies that the magnetotail volume influenced by a pseudobreakup is quite large in radial distance. We conclude that there is no definitive qualitative distinction between pseudobreakups and substorms but there is a continuum of states between the smell pseudobreakups and large substorms.

KW - DEEP GEOMAGNETIC TAIL

KW - ENERGETIC ION BURSTS

KW - MAGNETOSPHERIC SUBSTORMS

KW - MAGNETOTAIL

KW - SIGNATURES

KW - ONSET

KW - PLASMOIDS

KW - RECONNECTION

KW - DYNAMICS

KW - PARTICLE

UR - http://www.scopus.com/inward/record.url?scp=0003274118&partnerID=8YFLogxK

U2 - 10.1029/1999JA900118

DO - 10.1029/1999JA900118

M3 - статья

VL - 104

SP - 12263

EP - 12287

JO - Journal of Geophysical Research: Biogeosciences

JF - Journal of Geophysical Research: Biogeosciences

SN - 0148-0227

IS - A6

M1 - 1999JA900118

ER -