%0 Journal Article
%@holdercode {isadg {BR SPINPE} ibi 8JMKD3MGPCW/3DT298S}
%@nexthigherunit 8JMKD3MGPCW/3EU29DP 8JMKD3MGPCW/3EUFCFP
%@archivingpolicy denypublisher denyfinaldraft24
%@issn 1364-6826
%@resumeid
%@resumeid
%@resumeid
%@resumeid 8JMKD3MGP5W/3C9JH3D
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%@resumeid 8JMKD3MGP5W/3C9JGH3
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%@resumeid 8JMKD3MGP5W/3C9JHUD
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%@usergroup martaseeger
%3 Energy balance during.pdf
%X Geomagnetic storms are large disturbances in the Earth's magnetosphere caused by enhanced solar windmagnetosphere energy transfer. One of the main manifestations of a geomagnetic storm is the ring current enhancement. It is responsible for the decrease in the geomagnetic field observed at ground stations. In this work, we study the ring current dynamics during two different levels of magnetic storms. Thirty-three events are selected during the period 19812004. Eighteen out of 33 events are very intense (or super-intense) magnetic storms (Dst &#8722;250 nT) and the remaining are intense magnetic storms (&#8722;250<Dst &#8722;100 nT). Interplanetary data from spacecraft in the solar wind near Earth's orbit (ACE, IMP-8, ISEE-3) and geomagnetic indices (Dst and Sym-H) are analyzed. Our aim is to evaluate the interplanetary characteristics (interplanetary dawndusk electric field, interplanetary magnetic field component BS), the å parameter, and the total energy input into the magnetosphere (Wå) for these two classes of magnetic storms. Two corrections on the å energy coupling function are made: the first one is an already known correction in the magnetopause radius to take into account the variation in the solar wind pressure. The second correction on the Akasofu parameter, first proposed in this work, accounts for the reconnection efficiency as a function of the solar wind ram pressure. Geomagnetic data/indices are also employed to study the ring current dynamics and to search for the differences in the storm evolution during these events. Our corrected å parameter is shown to be more adequate to explain storm energy balance because the energy input and the energy dissipated in the ring current are in better agreement with modern estimates as compared with previous works. For super-intense storms, the correction of the Akasofu å is on average a scaling factor of 3.7, whilst for intense events, this scaling factor is on average 3.4. The injected energy during the main phase using corrected å can be considered a criterion to separate intense from very intense storms. Other possibilities of cutoff values based on the energy input are also investigated. A threshold value for the input energy is much more clear when a new classification on Dst=&#8722;165 nT is considered. It was found that the energy input during storms with Dst<&#8722;165 nT is double of the energy for storms with Dst>&#8722;165 nT.
%N 15
%T Energy Balance during Intense and Super-Intense Magnetic Storms using an Akasofu Epsilon Parameter Corrected by The Solar Wind Dynamic Pressure
%@secondarytype PRE PI
%K Super-intense magnetic storms, Energy transfer, å parameter.
%@visibility shown
%@group DGE-INPE-MCT-BR
%@group DGE-INPE-MCT-BR
%@group DGE-INPE-MCT-BR
%@group DGE-INPE-MCT-BR
%@group DGE-INPE-MCT-BR
%@group DGE-INPE-MCT-BR
%@group DGE-INPE-MCT-BR
%@group RSU-INPE-MCT-BR
%@secondarykey INPE-14987-PRE/9898
%@copyholder SID/SCD
%2 sid.inpe.br/mtc-m17@80/2007/10.19.20.43.02
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Centro Regional Sul de Pesquisas Espaciais (CRS/INPE)
%B Journal of Atmospheric and Solar-Terrestrial Physics
%P 1851-1863
%4 sid.inpe.br/mtc-m17@80/2007/10.19.20.42
%D 2007
%V 69
%A Lucas, Aline de,
%A Gonzalez, Walter Demé,
%A trio,
%A Echer, Ezequiel,
%A Guarnieri, Luis Fernando,
%A Lago, Alisson Dal,
%A Silva, Marlos Rockenbach da,
%A Vieria, Luis Eduardo Antunes,
%A Schuch, Nelson Jorge,
%@dissemination WEBSCI; PORTALCAPES; AGU; MGA; COMPENDEX.
%@area CEA