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Published in C. R. Kitchin, Astrophysical Techniques, 2020
These requirements for an observing site restrict the choice considerably and lead to a clustering of telescopes on the comparatively few optimum choices. Most are now found at high altitudes and on oceanic islands or with the prevailing wind from the ocean. Built-up areas tend to be small in such places, and the water vapour is usually trapped near sea level by an inversion layer. The long passage over the ocean by the winds tends to minimise dust and industrial pollution. The Antarctic plateau with its cold, dry and stable atmospheric conditions is also a surprisingly good observing site. The Arctic is also useful for radio studies of the aurora and so on with, for example, the European Incoherent Scatter (EISCAT) fixed and movable dishes operating at wavelengths of a few hundreds of millimetres. The EISCAT 3D is due to become operational in 2021 with five phased arrays, enabling three-dimensional (3D) studies of the ionosphere and upper atmosphere to be undertaken.
Initial results of stimulated radiation measurements during the HAARP campaign of September 2017
Published in Radiation Effects and Defects in Solids, 2018
A.D. Yellu, W.A. Scales, A. Mahmoudian, C. Siefring, P. Bernhardt
The first observations of stimulated electromagnetic radiation, more commonly known as stimulated electromagnetic emission (SEE), in an ionospheric heating experiment using the ionosphere heating facility now called the European Incoherent Scatter (EISCAT) radar near Tromsø, Norway was reported in (1) and the first formal theoretical framework of SEE observed during ionospheric heating was postulated in (2). Since then, ionosphere scientists have leveraged on SEE as tool for ionospheric diagnostics. Useful diagnostics from SEE spectra include ionospheric plasma characteristics such electron temperature, ionospheric plasma dynamics and ionospheric plasma turbulence (3). Experimental observations of stimulated radiation and its theoretical foundation are well established in the field of Laser Plasma Interactions (4) and thus intellectual transfer from this field has provided invaluable insight into SEE generated during ionosphere heating experiments.