author = "Saba, Marcelo Magalh{\~a}es Fares and Paiva, Amanda Rom{\~a}o de 
                         and Concollato, Luke C. and Warner, Tom A. and Schumann, Carina",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {University of Oxford} 
                         and {ZT Research} and {University of the Witwatersrand}",
                title = "Optical observation of needles in upward lightning flashes",
              journal = "Scientific Reports",
                 year = "2020",
               volume = "10",
               number = "1",
                pages = "e17460",
                month = "Dec.",
             abstract = "Why lightning sometimes has multiple discharges to ground is an 
                         unanswered question. Recently, the observation of small plasma 
                         structures on positive leaders re-ignited the search. These small 
                         plasma structures were observed as pulsing radio sources along the 
                         positive leader length and were named needles. Needles may be the 
                         missing link in explaining why lightning flickers with multiple 
                         discharges, but this requires further confirmation. In this work 
                         we present the first optical observations of these intriguing 
                         plasma structures. Our high-speed videos show needles blinking in 
                         slow motion in a sequential mode. We show that they are formed at 
                         unsuccessful leader branches, are as bright as the lightning 
                         leaders, and report several other optical characteristics.",
                  doi = "10.1038/s41598-020-74597-6",
                  url = "http://dx.doi.org/10.1038/s41598-020-74597-6",
                 issn = "2045-2322",
             language = "en",
           targetfile = "saba_optical.pdf",
        urlaccessdate = "18 jan. 2021"