Wakefield Formation by a Short Electron Beam in Quantum Nanowires

The basic properties of classical and quantum plasmas are discussed. Quantum plasmas behave differently due to high densities and low temperatures at nanometer scale in contrast to classical ones which are characterized by low densities and high temperatures. A literature survey is made to investigate the plasma phenomenon with quantum mechanical effects. Classical and quantum viewpoints are also presented to understand the free electron gas in metals. In particular, the excitation of stable plasmon wakefield is studied due to a short electron pulse propagating in axial direction of nanowire. The latter contains degenerate electrons and classical static ions. By using the Trivelpiece-Gould configuration and Fourier transform techniques, a general dispersion is obtained for the electrostatic plasmons and analyzed numerically. Nevertheless, an evolution equation for the wakefield is derived and carried out the stability analysis. In a gold nanowire, the amplitudes of wakefield become significantly modified by the variation of quantum diffraction, quantum exchange-correlations and mode quantization in the radial direction. The present findings may prove useful for investigating new radiation sources in the extreme-ultraviolet range.

Solar Wind control of Auroral Kilometric Radiation as measured by the Wind Satellite

<p><span>Auroral Kilometric Radiation (AKR) emanates from acceleration regions from which escaping particles also excite a number of phenomenon in the terrestrial ionosphere, notably aurorae.</span><span> As such, AKR emission is a barometer for particle precipitation, indicating activity in the magnetosphere. Observations suggest that the emission is mostly limited to the nightside, relating to bursty tail reconnection events. In this study we investigate the relationship between upstream interplanetary magnetic field and solar wind conditions, and the onset and morphology of corresponding AKR emission. Additionally, we explore the delay time between the arrival of solar wind phenomena at the magnetopause, and the onset of related AKR emission and morphology changes. Connections between AKR and solar wind observations allude to solar wind driving of energetic particle precipitation at different local times. The WAVES instrument on the Wind satellite has provided measurements of radio and plasma phenomenon at a range of locations for over two decades, and in this study a recently developed method is utilised to extract AKR bursts from WAVES data, enabling quantitative examination of AKR emission over statistical timescales.</span></p>