Open AccessKey features of >30 keV electron precipitation during high speed solar wind streams: A superposed epoch analysis
Author(s) -
Kavanagh A. J.,
Honary F.,
Donovan E. F.,
Ulich T.,
Denton M. H.
Publication year - 2012
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011ja017320
Subject(s) - riometer , precipitation , solar wind , physics , electron precipitation , substorm , astrophysics , environmental science , atmospheric sciences , ionosphere , meteorology , magnetosphere , geophysics , plasma , quantum mechanics
We present an epoch analysis of energetic (>30 keV) electron precipitation during 173 high speed solar wind streams (HSS) using riometer observations of cosmic noise absorption (CNA) as a proxy for the precipitation. The arrival of the co‐rotating interaction region (CIR) prior to stream onset, elevates the precipitation which then peaks some 12 h after stream arrival. Precipitation continues for several days following the HSS arrival. The MLT distribution of CNA is generally consistent with the statistical pattern explained via the substorm process, though the statistical deep minimum of CNA/precipitation does change during the HSS suggesting increased precipitation in the 15–20 MLT sector. The level of precipitation is strongly controlled by the average state of the IMF B Z component on the day prior to the arrival of the stream interface. An average negative IMF B Z will produce higher CNA across all L‐shells and MLT, up to 100% higher than an average positive IMF B Z .