Navegando por Assunto "Plasma bubbles"

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    Drift Velocity Estimation of Ionospheric Bubbles Using GNSS Observations
    (Advancing Earth and Space Sciences) Souza, Ana Lucia Christovam de; Camargo, Paulo de Oliveira; Muella, Marcio Tadeu de Assis Honorato; Tardelli‐Coelho, Flavia
    Equatorial plasma bubble (EPB) irregularities are large-scale plasma depleted structures that exist in the equatorial and low-latitude ionosphere. Thus, particularly in these regions, much attention must be given to the effects of the EPBs in the life critical applications based on global navigation satellite systems (GNSS). The study on the dynamics of plasma bubbles, particularly in the determination of their drift velocities, and their impact on ground-based augmentation system is of fundamental importance for civilian aviation. In this regard, we proposed a methodology to estimate the zonal drift velocities of the plasma bubble irregularities using slant total electron content (TEC) measurements derived from two spaced ground-based GNSS receivers. The experiments were performed with the purpose to evaluate if the drift velocities obtained using the methodology proposed in this study agree with the velocities deduced from all-sky imaging systems. The results revealed that the TEC-estimated mean eastward drift velocities were comparable with the values deduced from the airglow techniques, and with the results obtained from previous studies. Therefore, the methodology proposed in this work to infer the plasma bubble drift velocities seem to have the potential in future investigations to provide a new datasource in this field
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    Ground and satellite-based observations of ionospheric plasma bubbles and blobs at 5.65° latitude in the Brazilian sector
    (Elsevier) Agyei-Yeboah, Ebenezer; Fagundes, Paulo Roberto; Tardelli, Alexandre; Pillat, Valdir Gil; Pignalberi, Alessio; Kavutarapu, Venkatesh; Pezzopane, Michael; Vieira, Francisco
    This investigation uses simultaneous observations from all-sky imager system and an ionosonde collocated at Araguatins (5.65° S, 48.07° W and dip-latitude of 4.17° S), a near-equatorial region in Brazil. These simultaneous observations were used to investigate the occurrence of plasma bubbles and blobs in the field of the imaging system and their association with atypical range Spread-F signature in ionograms. Also, in-situ observation of plasma density from Swarm satellites were used to support the ground-based observations. Using a few cases, a methodology will be established to identify in the plasma blobs (atypical ESF) in the ionograms when there is the simultaneous observation of plasma bubbles and blobs in the field of view of the ionosonde. For this purpose, simultaneous sequence of OI 630.0 nm nightglow images and ionograms are presented for different case studies; 1. when there is the absence of a plasma bubble or blob, 2. when there is only the occurrence of plasma bubbles and 3. when there is the occurrence of plasma bubbles and blobs, in order to compare traces in the ionogram in all these case studies. With these we can cover all kinds of signatures in the ionograms corresponding to no irregularities, plasma bubbles only and plasma bubbles-blobs. These OI 630.0 nm nightglow and ionograms recorded simultaneously make it possible to establish a novel methodology to recognize in ionograms cases when there is the occurrence of Spread-F signature associated with bubble-blob in the FOV of the ionosonde.