@Article{HajraTsurEcheGonz:2014:SoCyPh,
author = "Hajra, Rajkumar and Tsurutani, Bruce T. and Echer, Ezequiel and
Gonzalez, Walter Demetrio",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Jet
Propulsion Laboratory (JPL) - California Institute of Technology}
and {Instituto Nacional de Pesquisas Espaciais (INPE)} and
{Instituto Nacional de Pesquisas Espaciais (INPE)}",
title = "Relativistic electron acceleration during high-intensity,
long-duration, continuous AE activity (HILDCAA) events: solar
cycle phase dependences",
journal = "Geophysical Research Letters",
year = "2014",
volume = "41",
number = "6",
pages = "1876–1881",
month = "Mar.",
keywords = "HILDCAAs, magnetospheric relativistic electrons, chorus waves,
high-speed streams, Alfv{\'e}n waves, solar cycle phases.",
abstract = "High-intensity, long-duration, continuous AE activity (HILDCAA)
intervals during solar cycle 23 (19952008) have been studied by a
superposed epoch analysis. It was found that HILDCAA intervals
order the solar wind velocity, temperature and density
(characteristic of high-speed solar wind intervals), the polar cap
potential, and various other geomagnetic indices well. The
interplanetary magnetic field Bz is generally negative, and the
Newell solar wind coupling function is high during HILDCAA events.
The HILDCAA intervals are well correlated with an enhancement of
magnetospheric relativistic (E\ >\ 2\ MeV)
electron fluxes observed at geosynchronous orbit with a delay of
~1.5\ days from the onset of the HILDCAAs. The response of
the energetic electrons to HILDCAAs is found to vary with solar
cycle phase. The initial electron fluxes are lower for events
occurring during the ascending and solar maximum (AMAX) phases
than for events occurring during the descending and solar minimum
(DMIN) phases. The flux increases for the DMIN phase events are
>50% larger than for the AMAX phase events. Although the solar
wind speeds during the DMIN phases were slightly higher and lasted
longer than during the AMAX phases, no other significant solar
wind differences were noted. It is concluded that electrons are
accelerated to relativistic energies most often and most
efficiently during the DMIN phases of the solar cycle. We propose
two possible solar UV mechanisms to explain this solar cycle
effect.",
doi = "10.1002/2014GL059383",
url = "http://dx.doi.org/10.1002/2014GL059383",
issn = "0094-8276",
label = "self-archiving-INPE-MCTI-GOV-BR",
language = "en",
targetfile = "RevisedManuscript.pdf",
urlaccessdate = "04 maio 2024"
}