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 = "25 jan. 2021"