VLF chorus emissions are very intense electromagnetic plasma waves that are naturally excited near the magnetic equatorial plane outside the plasmasphere. We introduce a mechanism of chorus excitation under conditions where known mechanisms become ineffective. This kind of excitation is related to the effective amplification of short electromagnetic pulses from the noise level even in a stable plasma. Obtained results can explain some important features of the chorus emissions without hiss-like. Hide

In this paper, a new GNSS troposphere water vapor tomography model with advantages of easy spread and application is proposed by using layered optimal polynomial functions. Under 6 scenarios, the results all show that the new troposphere tomography model with easier expression way has higher accuracy than that of the traditional, indicating that the new model we proposed could obtain the three-dimensional water vapor with high spatial and temporal resolution better. Hide

The variability of the Earth's ionosphere (the electrified region of the Earth's upper atmosphere) results from external forcing from above (through solar activity & space weather effects) and from below (via natural sources such as lightning storms and tectonics). Bombing raids over Europe during World War II were used to determine the quantitative impact of explosions on the ionosphere. It was found that raids using more than 300 tonnes of explosives weakened the ionosphere for up to 5 hours. Hide

The features of ULF waves are statistically studied on the magnetotail stretched magnetic field lines(8 R_E < R < 32 R_E) by using 8 years of THEMIS data. The occurrence rates of ULF waves are higher in the post-midnight region than pre-midnight region. The frequency decreases with increasing radial distance just between 8 and 16 R_E, it could be explained by much more standing waves in this region than in the region of 16–32 R_E. The wave frequency is higher after the substorm onset than before it. Hide

We proposed a new method to determine the scale height of water vapor, which will improve the quality of vertical constraints. Then, the smoothing factor in the horizontal constraint was determined based on ERA-Interim products. The evaluation results show that the water vapor density quality obtained by the optimized technique is 13.8 % better below 3.8 km and 8.1 % better above 3.8 km than that obtained by the traditional technique. Hide

We re-examine the physics of the magnetic mirror mode in its final state of saturation, the thermodynamic equilibrium, to demonstrate that the mirror mode is the analogue of a superconducting effect in a classical anisotropic-pressure space plasma. Two different spatial scales are identified which control the behaviour of its evolution. Hide

We present the dynamics of perturbations during a solar eclipse using rare parameters for eclipse study. Reduction in solar radiation and natural gas heating are the causal of the observed changes. The use of the bottomside F-layer parameters to probe the topside ionosphere established their interrelationship. Implication is that eclipse-caused perturbation could be better explained using some ionosonde parameters. Need for higher time resolution in IRI model to capture eclipse perturbations. Hide

This study shows the width of the meteor height distribution (FWHM) is well correlated with the atmospheric pressure not only experimentally but theoretically. From the correlation analysis, we newly found that the FWHM provides best estimation of the temperature at the height layer below the meteor peak height by 2–3 km. We also proved a meteor echo height ceiling effect (MHC) is primarily controlled by the atmospheric condition and this enables the FWHM to estimate the temperature accurately. Hide

By induction, ocean tides generate electromagnetic signals. Since the launch of magnetometer satellite missions, these signals are used increasingly to infer electric properties of the Earth. In many of these inversions, ocean tide models are used to generate oceanic tidal electromagnetic signals via electromagnetic induction. The studies main goal is to provide tide model errors for the electromagnetic inversion studies. Hide

We used sounding rockets to obtain 4 high-resolution profiles in the mesosphere over a limited area. We found consistent deep isothermal and adiabatic layers, but variable and finely structured turbulence preferentially in the lower stable mesosphere. Accompanying tracer releases showed horizontal winds in the lower thermosphere with extreme shears and 200 m/s winds under moderately disturbed geomagnetic conditions, and convective structures just below the mesopause. Hide

Based on comparisons of meteor radar measurements with HAMMONIA model simulations, we show that the differences exhibited by the semidiurnal solar tide (S2) observed at middle and high latitudes of the Northern Hemisphere between equinox times are mainly due to distinct behaviors of the migrating semidiurnal (SW2) and the non-migrating westward propagating wave number 1 semidiurnal (SW1) tidal components. Hide

GREEN (Global Radiation Earth ENvironment) is a new model providing particles fluxes at any location in the radiaiton belts, for energy between 1 keV to 10 MeV for electrons and between 1 keV and 800 MeV for protons. This model is composed of global models: AE8/AP8 and SPM and local models: SLOT model, OZONE, IGE-2006 for electrons and OPAL and geostationary model for protons. Hide

The novelty of this paper resides in the fact that it addresses the termosphere/ionosphere coupling in a mid-latitude site in north Africa. We have used Fabry-Perot measurements of the thermospheric winds and wide-angle camera detection of ionospheric structurers, at an altitude of about 250 km. We have also used GPS data to extract the TEC over the studied area. We have focused our study on the 27 Feb geomagnetic storm. Hide