Bibliography

AMICal Sat: A sparse RGB imager on board a 2U cubesat to study the aurora

AMICal sat, a dedicated 2U cubesat, has been developed, in order to monitor the auroral emissions, with a dedicated imager. It aims to help to reconstruct the low energy electrons fluxes up to 30 keV in Earth auroral regions. It includes an imager entirely designed in Grenoble University Space Center. The imager uses a 1.3 Mpixels sparse RGB CMOS detector and a wide field objective (f=22.5 mm). The satellite platform has been built by the polish company Satrevolution. Launched September, 3rd, 2020 from Kuru (French Guyana) on board the Vega flight 16, it produces its first images in October 2020. The aim of this paper is to describe the design of the payload especially the optics and the proximity electronics, to describe the use of the payload for space weather purpose. A preliminary analysis of a first image showing the relevance of such an instrument for auroral monitoring is performed. This analysis allowed to reconstruct from one of the first images the local electron input flux at the top of the atmosphere during the exposure time.

Barthelemy, Mathieu; Robert, Elisa; Kalegaev, Vladimir; Grennerat, Vincent; Sequies, Thierry; Bourdarot, Guillaume; Le Coarer, Etienne; Correia, Jean-Jacques; Rabou, Patrick;

Published by: IEEE Journal on Miniaturization for Air and Space Systems      Published on:

YEAR: 2022     DOI: 10.1109/JMASS.2022.3187147

Aerospace electronics; AURORA; cubesat; Detectors; imager; Instruments; Ion radiation effects; magnetosphere; Monitoring; Satellites

Transpolar Arcs: Seasonal Dependence Identified by an Automated Detection Algorithm

Transpolar arcs (TPAs) are auroral features that occur polewards of the main auroral oval suggesting that the magnetosphere has acquired a complicated magnetic topology. They are primarily a northward interplanetary magnetic field (IMF) auroral phenomenon, and their formation and evolution have no single explanation that is unanimously agreed upon. An automated detection algorithm has been developed to detect the occurrence of TPAs in UV images captured from the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) instrument onboard the Defense Meteorological Satellite Program (DMSP) spacecraft, in order to further study their occurrence. Via this detection algorithm TPAs are identified as a peak in the average radiance intensity poleward of 12.5° colatitude, in two or more of the wavelengths/bands sensed by SSUSI. Using the detection algorithm for the years 2010 to 2016, over 5000 images containing TPAs are identified. The occurrence of these TPAs shows a seasonal dependence, with more arcs being visible in the winter hemisphere. The orbital plane of DMSP has been investigated as a possible explanation of the dependences in the results of the detection algorithm. For the spacecraft of interest this leads to a preferential observation of the northern hemisphere with the detection algorithm missing TPAs in the southern hemisphere around 01–06 UT. No seasonal bias has been found for these spacecraft. We discuss the ramifications of these findings in terms of proposed TPA generation mechanisms and suggest reasons for the seasonal dependence including it being a reflection of probability of seeing TPAs due to visibility.

Bower, G.; Milan, S.; Paxton, L.; Imber, S.;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2022     DOI: 10.1029/2021JA029743

auroras; magnetosphere; transpolar arc

Latitudinal Dependence of Ionospheric Responses to Some Geomagnetic Storms during Low Solar Activity

The Latitudinal dependence in the response of the Ionospheric F2-layer electron density (NmF2) and peak height (hmF2) to three geomagnetic storms of May and August 2010 has been examined. The data-sets used for the study were obtained from Ilorin, Nigeria (1.87° S/76.67° E), San Vito, Italy (34.68° N/90.38° E), Hermanus, South Africa (42.34° S/82.15° E), and Pruhonice, Czech Republic (45.66° N/90.38° E) geomagnetic coordinates. The quiet time result shows that the rise in NmF2 began earlier at San Vito, followed by Pruhonice. The rate of ionization was observed to be highest in Ilorin, while, the rate of decay in NmF2 is faster at Hermanus. For disturbed NmF2 condition, remarkable similarities in the NmF2 responses during geomagnetic storms were recorded from Hermanus in the mid-latitude and Ilorin, an equatorial station. NmF2 enhancements (\textgreater6 hours) that is consistent with the increase in hmF2 were observed at all the mid-latitude stations during the main phase of the 02 May, 2010 storm, without any noticeable change over ILN. Similarly, 12 hours of positive phase was observed at ILN and HMN, with 30 hours of NmF2 depletions at PRN and SVT during the recovery phase. ILN is in the equatorial Trough, so most of the NmF2 produced at this region is lifted to the higher latitudes by the fountain effect during the main phase. The suppression of the zonal electric field at ILN is responsible for the NmF2 enhancement during the recovery phase, while the mid-latitude responses have been attributed to the effect of the thermospheric winds and neutral composition changes.

Joshua, B.; Adeniyi, J.; Olawepo, A.; Rabiu, Babatunde; Daniel, Okoh; Adebiyi, S.; Adebesin, B.; Ikubanni, S.; Abdurahim, B.;

Published by: Geomagnetism and Aeronomy      Published on: may

YEAR: 2021     DOI: 10.1134/S0016793221030063

Electric field; Electron density; Geomagnetic storms; magnetosphere; peak height

Polar cap arcs correlated with solar wind entry at the high latitude magnetosphere

Polar cap arcs are sun-aligned aurora structures occurring during northward turnings of the Interplanetary Magnetic Field (IMF) B_z component. At the same time, a new region of solar wind entry at the high latitude magnetosphere, tailward of the cusp region, was found recently at the periods of northward IMF B_z. We propose a study to see the relationship of these entry events with the transpolar arc formation. Data of Global Ultraviolet Imager (GUVI) onboard TIMED mission is examined to see the transpolar aurora arcs during the given time periods of the solar wind entry. Initial results show that in approximately 20\% of cases transpolar arcs occur related to the solar wind entry processes.

Mailyan, B.; Shi, Q.; Gou, X.;

Published by:       Published on:

YEAR: 2014     DOI: 10.1109/URSIGASS.2014.6929926

aurora interplanetary; GUVI; magnetic fields; magnetosphere; solar wind; TIMED