T . B . Leyser

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In November 1999 the EISCAT high-power, high-frequency (HF) facility located near Tromsø, Norway, was used to create artificial plasma turbulence in the ionosphere. During the experiment the EISCAT 224 MHz radar and sometimes the 931 MHz radar were used to obtain measurements of incoherent scatter ion and plasma lines, and artificially enhanced spectra of(More)
[1] In recent years, large electron temperature increases of 300% (3000 K above background) caused by powerful HF-radio wave injection have been observed during nighttime using the EISCAT incoherent scatter radar near Tromsø in northern Norway. In a case study we examine the spatial structure of the modified region. The electron heating is accompanied by(More)
Optical emissions and incoherent scatter radar data obtained during high-frequency electromagnetic pumping of the ionospheric plasma from the ground give data on electron energization in an energy range from 2 to 100 eV. Optical emissions at 4278 A from N2+ that require electrons with energies above the 18 eV ionization energy give the first images ever of(More)
Simultaneous measurements of enhanced airglow at 6300 Å and plasma temperatures from transmitting a powerful high frequency electromagnetic pump wave from the EISCAT-Heating facility into the ionospheric F region at auroral latitudes are reported. The airglow was detected with the Auroral Large Imaging System in northern Sweden and the background plasma(More)
Experimental results are presented of pumping ionospheric plasma with a radio wave carrying orbital angular momentum (OAM), using the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Optical emissions from the pumped plasma turbulence exhibit the characteristic ring-shaped morphology when the pump beam carries OAM. Features of(More)
The shape of the electron energy distribution has long been a central question in the field of high-frequency radio-induced optical emission experiments. This report presents estimates of the electron energy distribution function, , from 0 to 60 based on optical multiwavelength (6300, 5577, 8446, 4278 ̊ ) data and 930incoherent scatter radar measurements(More)
Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary(More)
A major goal of ionospheric high power radio wave modiication experiments is the unraveling of the physics of the plasma turbulence created by the high frequency (HF) pump wave. The signature of this turbulence can be seen in the plasma line spectrum obtained from an incoherent scatter (sometimes called Thomson scatter) very high or ultra high frequency(More)
Hall, J-O. 2004. Interaction Between Electromagnetic Waves and Localized Plasma Oscillations. Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 985. 43 pp. Uppsala. ISBN 91-554-5982-X This thesis treats interaction between electromagnetic waves and localized plasma oscillations. Two(More)
An analytic description of electromagnetic waves in an inhomogeneous plasma is applied to investigate excitation of localized rotating waves below the lower hybrid frequency through scattering of fast magnetosonic waves on a density cavity. The magnetosonic wave is focused to left-handed rotating oscillations. We find the amplitude of the localized(More)