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Strathprints serves world leading Open Access research by the University of Strathclyde, including research by the Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), where research centres such as the Industrial Biotechnology Innovation Centre (IBioIC), the Cancer Research UK Formulation Unit, SeaBioTech and the Centre for Biophotonics are based.

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Laboratory reproduction of auroral magnetospheric radio wave sources

Ronald, K. and Speirs, David and McConville, S.L. and Gillespie, K.M. and Phelps, A.D.R. and Cross, A.W. and Bingham, R. and Robertson, C.W. (2008) Laboratory reproduction of auroral magnetospheric radio wave sources. In: 2008 ICTP International Workshop on the Frontiers of Modern Plasma Physics, 2008-07-14 - 2008-07-25.

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Abstract

Auroral Kilometric Radiation, AKR, occurs naturally in the polar regions of the Earth's magnetosphere where electrons are accelerated by electric fields into the increasing planetary magnetic dipole. Here conservation of the magnetic moment converts axial to rotational momentum forming a horseshoe distribution in velocity phase space. This distribution is unstable to cyclotron emissions and radiation is emitted in the X-mode. In the laboratory a 75-85kV electron beam of 5-40A was magnetically compressed by a system of solenoids. Results are presented for an electron beam gyrating at cyclotron frequencies of 4.42GHz and 11.7GHz resonating with near cut-off TE01 and TE03 modes respectively. Measurements of the electron transport combined with numerical simulations demonstrated that a horseshoe distribution function was formed in electron velocity space. Analysis of the experimental measurements allowed the inference of the 1D number density as a function of the electron beam pitch angle. The total power emitted experimentally was ~19-35 kW with a maximum RF emission efficiency of ~2%. These results were compared to those obtained numerically using a 2D PiC code KARAT with a maximum efficiency of 2% predicted for the same mode and frequency, consistent with astrophysical and theoretical results.