@Article{LopezGVRCERB:2015:DeSYDu,
author = "Lopez, R. E. and Gonzalez Alarcon, Walter Dem{\'e}trio and
Vasyliunas, V. and Richardson, I. G. and Cid, C. and Echer,
Ezequiel and Reeves, G. D. and Brandt, P. C.",
affiliation = "{University of Texas at Arlington} and {Instituto Nacional de
Pesquisas Espaciais (INPE)} and {Max-Planck-Institut f{\"u}r
Sonnensystemforschung} and {University of Maryland} and
{Universidad de Alcal{\'a}} and {Instituto Nacional de Pesquisas
Espaciais (INPE)} and {Los Alamos National Laboratory} and {The
Johns Hopkins Applied Physics Laboratory}",
title = "Decrease in SYM-H during a storm main phase without evidence of a
ring current injection",
journal = "Journal of Atmospheric and Solar-Terrestrial Physics",
year = "2015",
volume = "134",
pages = "118--129",
month = "Nov.",
keywords = "Magnetic storms, Ring current, Substorm particle injections, Polar
cap flux.",
abstract = "Changes in the Dst index, or the similarly constructed
high-resolution SYM-H index, are thought to indicate changes in
the total energy content of the ring current. However, this is not
always the case. In this paper we examine an intense (SYM-H
\∼ \−435 nT) magnetic storm that occurred on March
31, 2001. The arrival at Earth of strongly southward IMF produced
an immediate negative response in the SYM-H index. While energetic
particle and magnetometer data from geosynchronous orbit and inner
magnetosphere energetic neutral atom imaging indicate that two
substorm injections took place during the main phase, there was
about one hour when the SYM-H decreased more than 200 nT with no
evidence in the data for ring current enhancement. Instead the
near-Earth magnetotail exhibited a growth phase indicative of a
strong, growing cross-tail current, with the large substorm
expansion phase and the associated injection of energetic
particles coming significantly later. Data from the DMSP
spacecraft demonstrate that the polar cap flux grew rapidly in
response to the strongly southward IMF. We present observations
showing that the decrease in SYM-H occurred when polar cap flux
was increasing and there was no evidence of injection into the
ring current. Our findings strongly support the relationship
between Dst and the polar cap flux proposed by theoretical studies
that determined that the tail current system could be a
significant contributor to Dst.",
doi = "10.1016/j.jastp.2015.09.016",
url = "http://dx.doi.org/10.1016/j.jastp.2015.09.016",
issn = "1364-6826",
language = "en",
targetfile = "2015_lopez.pdf",
urlaccessdate = "27 abr. 2024"
}