Browsing by Author "Raulin, Jean-Pierre"
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Item Restricted Atmospheric electric field variations and lower ionosphere disturbance during the total solar eclipse of 2010 July 11(Elsevier, 2016-11) Tacza, José C.; Raulin, Jean-Pierre; Macotela, Edith L.; Norabuena Ortiz, Edmundo; Fernández, GermánIn this paper, we study the variations of atmospheric electric field during the total solar eclipse (TSE) of July 11, 2010, at Complejo Astronómico El Leoncito (CASLEO). These variations observed with two identical sensors separated by 0.4 km, show a significant increase (∼55 V/m) when compared with averaged values measured during previous and subsequent fair weather days. Furthermore, identical changes are detected on the measured phases of Very Low Frequency waves received at CASLEO. The latter suggests a possible connection between the lower ionosphere and the lower atmosphere during the period of the eclipse.Item Open Access First very low frequency detection of short repeated burstds from MAGNETAR SGR J1550−5418(American Astronomical Society, 2010-08) Tanaka, Y. T; Raulin, Jean-Pierre; Bertoni, Fernando C. P.; Fagundes, P. R.; Chau Chong Shing, Jorge Luis; Schuch, N. J; Hayakawa, M.; Hobara, Y.; Terasawa, T.; Takahashi, T.We report on the first detection of ionospheric disturbances caused by short repeated gamma-ray bursts from the magnetar SGR J1550−5418. Very low frequency (VLF) radio wave data obtained in South America clearly show sudden amplitude and phase changes at the corresponding times of eight soft gamma-ray repeater bursts. Maximum amplitude and phase changes of the VLF signals appear to be correlated with the gamma-ray fluence. On the other hand, VLF recovery timescales do not show any significant correlation with the fluence, possibly suggesting that the bursts’ spectra are not similar to each other. In summary, Earth’s ionosphere can be used as a very large gamma-ray detector and the VLF observations provide us wit.