@Article{LucasGEGLSVS:2007:EnBaDu,
               author = "Lucas, Aline de and Gonzalez, Walter Dem{\'e} and trio and Echer, 
                         Ezequiel and Guarnieri, Luis Fernando and Lago, Alisson Dal and 
                         Silva, Marlos Rockenbach da and Vieria, Luis Eduardo Antunes and 
                         Schuch, Nelson Jorge",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and {Centro 
                         Regional Sul de Pesquisas Espaciais (CRS/INPE)}",
                title = "Energy Balance during Intense and Super-Intense Magnetic Storms 
                         using an Akasofu Epsilon Parameter Corrected by The Solar Wind 
                         Dynamic Pressure",
              journal = "Journal of Atmospheric and Solar-Terrestrial Physics",
                 year = "2007",
               volume = "69",
               number = "15",
                pages = "1851--1863",
             keywords = "Super-intense magnetic storms, Energy transfer, å parameter.",
             abstract = "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 \−250 nT) and the 
                         remaining are intense magnetic storms (\−250<Dst 
                         \−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=\−165 nT is considered. It was found that the energy 
                         input during storms with Dst<\−165 nT is double of the 
                         energy for storms with Dst>\−165 nT.",
           copyholder = "SID/SCD",
                 issn = "1364-6826",
             language = "en",
           targetfile = "Energy balance during.pdf",
        urlaccessdate = "02 maio 2024"
}