@Article{HajraTsEcGoBrViSa:2015:ArPrCI,
author = "Hajra, Rajkumar and Tsurutani, Bruce T. and Echer, Ezequiel and
Gonzalez Alarcon, Walter Dem{\'e}trio and Brum, Christiano
Garnett Marques and Vieira, Luis Eduardo Antunes and Santolik,
Ondrej",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {} and
{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto
Nacional de Pesquisas Espaciais (INPE)} and {} and {Instituto
Nacional de Pesquisas Espaciais (INPE)}",
title = "Relativistic electron acceleration during HILDCAA events: are
precursor CIR magnetic storms important?",
journal = "Earth, Planets and Space",
year = "2015",
volume = "67",
keywords = "HILDCAAs, High-speed streams, CIRs, Chorus plasma waves, Radiation
belt, Magnetospheric relativistic electrons, Solar wind,
Geomagnetic storms.",
abstract = "We present a comparative study of high-intensity long-duration
continuous AE activity (HILDCAA) events, both isolated and those
occurring in the {"}recovery phase{"} of geomagnetic storms
induced by corotating interaction regions (CIRs). The aim of this
study is to determine the difference, if any, in relativistic
electron acceleration and magnetospheric energy deposition. All
HILDCAA events in solar cycle 23 (from 1995 through 2008) are used
in this study. Isolated HILDCAA events are characterized by
enhanced fluxes of relativistic electrons compared to the
pre-event flux levels. CIR magnetic storms followed by HILDCAA
events show almost the same relativistic electron signatures.
Cluster 1 spacecraft showed the presence of intense whistler-mode
chorus waves in the outer magnetosphere during all HILDCAA
intervals (when Cluster data were available). The storm-related
HILDCAA events are characterized by slightly lower solar wind
input energy and larger magnetospheric/ionospheric dissipation
energy compared with the isolated events. A quantitative
assessment shows that the mean ring current dissipation is similar
to 34 % higher for the storm-related events relative to the
isolated events, whereas Joule heating and auroral precipitation
display no (statistically) distinguishable differences. On the
average, the isolated events are found to be comparatively weaker
and shorter than the storm-related events, although the
geomagnetic characteristics of both classes of events bear no
statistically significant difference. It is concluded that the CIR
storms preceding the HILDCAAs have little to do with the
acceleration of relativistic electrons. Our hypothesis is that
similar to 10-100-keV electrons are sporadically injected into the
magnetosphere during HILDCAA events, the anisotropic electrons
continuously generate electromagnetic chorus plasma waves, and the
chorus then continuously accelerates the high-energy portion of
this electron spectrum to MeV energies.",
doi = "10.1186/s40623-015-0280-5",
url = "http://dx.doi.org/10.1186/s40623-015-0280-5",
issn = "1343-8832",
language = "en",
urlaccessdate = "04 maio 2024"
}