Peculiarities of 630.0 and 557.7 nm emissions in the main ionospheric trough: March 17, 2015

Peculiarities of 557.7 and 630.0 nm emissions observed in the second step of the magnetic storm main phase at the mid-latitude observatory Tory (52° N, 103° E) on March 17, 2015 are compared with the changes in ionospheric parameters above this station, detected from ionospheric sounding data and total electron content maps. We have found that the intensity of the 557.7 and 630.0 nm emissions noticeably increased after the observatory entered into the longitudinal sector of the developed main ionospheric trough (MIT). The most powerful synchronous increases in intensities of the two emissions are associated with amplification of the westward electrojet during strengthening of the magnetospheric convection. We study the dependence of the ratios between the intensities of 630.0 nm emission recorded in the north, zenith, and south directions on the position of emitting regions relative to the MIT bottom. The SAR arc is shown to appear initially near the bottom of the MIT polar wall and approach the zenith of the station during registration of F3s reflections by an ionosonde, which indicate the presence of a polarization jet near the observation point.

Recovery of Ionospheric Signals Using Fully Convolutional DenseNet and Its Challenges

The technique of active ionospheric sounding by ionosondes requires sophisticated methods for the recovery of experimental data on ionograms. In this work, we applied an advanced algorithm of deep learning for the identification and classification of signals from different ionospheric layers. We collected a dataset of 6131 manually labeled ionograms acquired from low-latitude ionosondes in Taiwan. In the ionograms, we distinguished 11 different classes of the signals according to their ionospheric layers. We developed an artificial neural network, FC-DenseNet24, based on the FC-DenseNet convolutional neural network. We also developed a double-filtering algorithm to reduce incorrectly classified signals. That made it possible to successfully recover the sporadic E layer and the F2 layer from highly noise-contaminated ionograms whose mean signal-to-noise ratio was low, SNR = 1.43. The Intersection over Union (IoU) of the recovery of these two signal classes was greater than 0.6, which was higher than the previous models reported. We also identified three factors that can lower the recovery accuracy: (1) smaller statistics of samples; (2) mixing and overlapping of different signals; (3) the compact shape of signals.

Peculiarities of 630.0 and 557.7 nm emissions in the main ionospheric trough: March 17, 2015

Peculiarities of 557.7 and 630.0 nm emissions observed in the second step of the magnetic storm main phase at the mid-latitude observatory Tory (52° N, 103° E) on March 17, 2015 are compared with the changes in ionospheric parameters above this station, detected from ionospheric sounding data and total electron content maps. We have found that the intensity of the 557.7 and 630.0 nm emissions noticeably increased after the observatory entered into the longitudinal sector of the developed main ionospheric trough (MIT). The most powerful synchronous increases in intensities of the two emissions are associated with amplification of the westward electrojet during strengthening of the magnetospheric convection. We study the dependence of the ratios between the intensities of 630.0 nm emission recorded in the north, zenith, and south directions on the position of emitting regions relative to the MIT bottom. The SAR arc is shown to appear initially near the bottom of the MIT polar wall and approach the zenith of the station during registration of F3s reflections by an ionosonde, which indicate the presence of a polarization jet near the observation point.

RUSSIAN HIGH-LATITUDE NETWORK OF OBLIQUE IONOSPHERIC SOUNDING

The network for monitoring the high-latitude ionosphere by the method of oblique ionospheric sounding deployed in the Russian Arctic region is considered. The study describes the main results of operational data processing for studying the high-latitude ionosphere and determining the conditions for the optimum operation of radio communication systems and over-the-horizon radars in this region. The study demonstrates the potential of the network as a tool for the remote diagnostics of parameters of small-scale artificial ionospheric irregularities induced by powerful HF radio waves in the mid-latitude ionospheric F-region.

ExPRES Modeling of Auroral Radio Source Occultation observed by Galileo Application to JUICE and Juno

<p>The ExPRES code simulates exoplanetary and planetary auroral radio emissions. It could be used to predict and interpret Jupiter’s radio emissions in the hectometric and decametric range. In this study, we model the occultations of the Jovian auroral radio emissions during the Galilean moons flybys by the Galileo spacecraft. In this study, we focus on auroral radio emissions, configuring the ExPRES simulations runs with typical radio source physical parameters. We compare the simulations run results with the actual Galileo/PWS observations, and show that we accurately model the temporal occurrence of the occultations in the whole spectral range observed by Galileo. We can then predict auroral radio emission occultations by the Galilean moons for the Juno and JUICE missions. ExPRES will be used by the JUICE/RPWI (Radio Plasma Waves Investigation) team to prepare its operation planning during the Galilean moon flybys for, e.g., the Galilean moon ionosphere characterization science objective, with passive ionospheric sounding during ingress and egress of Jovian radio source occultations. </p>