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We constructed a far ultraviolet (FUV) all sky map based on observations from the Far Ultraviolet Imaging Spectrograph (FIMS) aboard the Korean microsatellite STSAT-1. For the $\sim 20\%$ of the sky not covered by FIMS observations, predictions from a deep artificial neural network were used. Seven datasets were chosen for input parameters, including five all sky maps of Hα, E(B-V), N(HI), and two X-ray bands, with Galactic longitudes and latitudes. 70% of the pixels of the observed FIMS dataset were randomly selected for training as target parameters and the remaining 30% were used for validation. A simple four-layer neural network architecture, which consisted of three convolution layers and a dense layer at the end, was adopted, with an individual activation function for each convolution layer; each convolution layer was followed by a dropout layer. The predicted FUV intensities exhibited good agreement with Galaxy Evolution Explorer (GALEX) observations made in a similar FUV wavelength band for high Galactic latitudes. As a sample application of the constructed map, a dust scattering simulation was conducted with model optical parameters and a Galactic dust model for a region that included observed and predicted pixels. Overall, FUV intensities in the observed and predicted regions were reproduced well.

In this paper, we derive the quantum Vlasov equation as a differential equation of the Wigner function directly from the electromagnetic Schrödinger equation and apply it to the plasma waves propagating in the direction parallel to the ambient magnetic field. The upper branches of the L and R waves in the plot of (ω, k) space have dispersion relations similar to those of their respective classical waves, with only minor corrections. The lower R-wave branch also has a dispersion relation similar to that of the classical whistler wave for a small wavenumber k. However, the dispersion curve encounters a region of anomalous dispersion, exhibiting a negative group velocity, as k increases. Furthermore, the branch becomes a damping wave as k increases above a certain critical value and eventually the wave becomes ill-defined for larger k values.

Monitoring the Earth's radiation belt by Low-Earth-Orbit (LEO) satellites has a long history and complemented observations near the high-altitude equatorial plane. However, most of the previous LEO missions suffered from limitations in energy resolution, energy range, L-shell coverage, or the mission lifetime, which leave room for further improvement in this topic. Here we present multi-year (January 2019~February 2021) observations of energetic (0.03 MeV~1.8 MeV) electrons by the Korean NextSat-1 (altitude~575 km) with high energy resolution (0.006-0.4 MeV) and seamless L-shell coverage. For <80 keV electrons, the slot-region outer edge moves inward with increasing geomagnetic activity, which agrees with previous Van Allen Probes reports. The behavior is more conspicuous for lower-energy electrons. Latitudinal profiles of outer-belt electron flux are smoother equatorward of the geosynchronous footprint latitudes (|MLAT|~66 o ) than poleward. The NextSat-1 electron flux is positively correlated to geosynchronous observations, with the coefficient generally higher for higher electron energies. Also, both the geosynchronous and NextSat-1 data exhibit similar spectral indices close to -3 in the log-log space. All these results complement and expand previous knowledge on energetic electrons. The main findings are discussed in the context of existing literature.

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