The paper discusses the excitation of monochromatic ELF/VLF electromagnetic waves produced by HF heating facilities currents in the nighttime ionosphere. The ground-based magnetic field is predominantly located under the source and wave has typical for whistler right hand polarization, but left hand polarization at large distances from the source. About half of the source energy propagates upward and approximately twenty percent propagates to the Earth-ionosphere waveguide.

The electrical conductivity of the Earth's ionosphere is an important parameter in the study of the the polar, auroral currents that produce magnetic disturbances on the ground. Yet the values of the conductances, and how they vary, are not known with great precision. In our study we tested a method for deriving the conductivity values that requires use of three empirical models, for the electric fields above the ionosphere and the magnetic field perturbations both on the ground and in space.

When the magnetised solar wind meets the plasma surrounding a comet, the magnetic field is enhanced in front of the comet and the field lines are draped around it. This happens because electric currents are induced in the plasma. When these currents flow through the plasma, they can generate waves. In this article we present observations of ion acoustic waves, which is a kind of sound waves in a plasma, detected by instruments on the Rosetta spacecraft near comet 67P/Churyumov-Gerasimenko.

We present observations of a new type of small-scale aurora-like feature, which we name Fragmented Aurora-like Emissions (FAEs). Whereas aurora is caused by particle precipitation, FAEs seem to be locally generated in the ionosphere, hence the term aurora-like. We analyse data from multiple instruments located near Longyearbyen on Svalbard to derive the main characteristics of FAEs. They seem to occur as two types within a narrow altitude region – individually or in regularly spaced groups.

Using the RENU2 rocket and ground based instruments, we show that significant parts of the blue aurora above Svalbard at the time of launch was sunlit aurora. Sunlit aurora occurs when nitrogen molecules are ionised by extreme UV sunlight and subsequently hit by electrons from the Sun, resulting in blue/violet emissions. Understanding the source of an auroral emission gives insight into the interaction between the Sun and the Earths upper atmosphere.

This work explores the role of EISCAT 3D as a tool for planetary mapping. Due to the challenges inherent in detecting the signals reflected from far-away bodies, we have concluded that only the Moon is a viable mapping target. We estimate the impact of the ionosphere on lunar mapping, concluding that it's distorting effects should be easily manageable. EISCAT 3D will be useful for mapping the lunar nearside due to it's previously unused frequency (233 MHz) and it's interferometric capabilities.