Browsing by Autor "C. A. O. B. Figueiredo"

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Signature of white bubbles in the equatorial ionosphere
(2024) H. Takahashi; C. A. O. B. Figueiredo; C. M. Wrasse; Diego Barros; C. S. Carmo; A. J. Carrasco; R. A. Buriti; Igo Paulino; Fábio Egito; Luiz Fillip Rodrigues Vital
<title>Abstract</title> From airglow OI 630 nm observations in the low-latitude ionosphere, we observed an enhancement of the emission rate inside of plasma bubbles (EPBs). It occurred, on some occasions, after the local midnight during the equinox seasons. The all-sky imager has been operated at Bom Jesus da Lapa (BJL) (13.3°S, 43.5°W, dip.14.1°S). In the night of 7–8 October 2021, a dark plasma bubble turned into a bright one due to an enhancement of the OI 630 nm emission rate, which we call it as White Bubble (WhB). Prior to the WhB appearance, the imager detected a presence of Midnight Brightness Wave (MBW) moving rapidly from the equator to the south of BJL. At the same time, a downward movement of the height of the F-layer was observed at Cachoeira Paulista (22.7 °S, 45.0 °W, dip. 18.1°S). We further observed that the WhB extended equatorward when the EPB eastward drift increased. Similar WhBs were observed on seven nights during 2021–2022. These observational facts suggested that the MBW interacted with EPB, causing the depletion inside of EPB to be filled with plasma, resulting in the generation of WhB.
Signature of white bubbles in the equatorial ionosphere
(2025) H. Takahashi; C. A. O. B. Figueiredo; C. M. Wrasse; Diego Barros; C. S. Carmo; A. J. Carrasco; R. A. Buriti; Igo Paulino; Francisco Edson Mendonça Gomes; Luiz Fillip Rodrigues Vital
<title>Abstract</title> From airglow OI 630 nm observations in the low-latitude ionosphere, we identified an enhancement in the emission rate inside Equatorial Plasma Bubbles (EPBs) on certain occasions after local midnight during equinox seasons. On the night of 7–8 October 2021, an all-sky imager, operated at Bom Jesus da Lapa (BJL) (13.3°S, 43.5°W, dip 14.1°S), observed a dark plasma bubble transitioning into a bright one due to an enhancement of the OI 630 nm emission rate, a phenomenon we refer to as a "White Bubble" (WhB). Prior to the appearance of the WhB, the imager detected a Midnight Brightness Wave (MBW) rapidly moving southward from the equator. Concurrently, a downward movement of the F-layer's height was observed at Cachoeira Paulista (22.7°S, 45.0°W, dip 18.1°S). The WhB extended equatorward when the EPB's eastward drift speed increased. Similar WhBs were observed on seven nights during 2021–2022. These observations suggest that the MBW interacted with the EPB, causing plasma depletion within the EPB to be filled, ultimately generating a WhB.